Talks
dprn-2026 11 Jun 2026 2 11–12 June 2026 Helsinki, Finland 4th European Digital Platform Research Network Summit (EU-DPRN) Does Digital Platform Interoperability Deliver on Its Promises? An Empirical Test of Theory Conference Page https://www.eudprn.com Paper https://osf.io/preprints/socarxiv/6wsrq
2026
4th European Digital Platform Research Network Summit (EU-DPRN)
Does Digital Platform Interoperability Deliver on Its Promises? An Empirical Test of Theory
marketplace-2026 3 Jun 2026 2 3–4 June 2026 University of St. Gallen, Switzerland The Oxford Handbook of Marketplaces Workshop Why Online Marketplaces Centralise: The Limits of Decentralised Internet Platforms. Workshop for contributors of the forthcoming Oxford Handbook to discuss our draft chapters.
2026
The Oxford Handbook of Marketplaces Workshop
Why Online Marketplaces Centralise: The Limits of Decentralised Internet Platforms.
Workshop for contributors of the forthcoming Oxford Handbook to discuss our draft chapters.
2026-keynote2 14 May 2026 1 14 May 2026 Slovenia Keynote Speech, By Invitation Who Owns the Internet Today? How Businesses Can Break Free 45 minute keynote speech for an audience of 700 business managers. The internet was meant to be open, decentralised, and full of opportunity. Instead, much of today’s digital economy is controlled by a small number of platforms, algorithms, and gatekeepers that shape visibility, customer access, and the rules of competition. In this keynote, Philipp Riederle explores how that happened, why it matters for brands and businesses, and how companies can break free from digital dependence. Event Page https://sof.si/program/dogodek/internet-kdo-ga-zares-obvladuje Press Article https://www.media-marketing.com/en/news/philipp-riederle-the-internet-is-no-longer-a-space-of-freedom-but-a-space-of-control/
2026
Keynote Speech, By Invitation
Who Owns the Internet Today? How Businesses Can Break Free
45 minute keynote speech for an audience of 700 business managers.
Abstract
The internet was meant to be open, decentralised, and full of opportunity. Instead, much of today’s digital economy is controlled by a small number of platforms, algorithms, and gatekeepers that shape visibility, customer access, and the rules of competition. In this keynote, Philipp Riederle explores how that happened, why it matters for brands and businesses, and how companies can break free from digital dependence.
2026-keynote1 11 May 2026 11 May 2026 Zürich, Switzerland Keynote Speech, By Invitation Resilient into the future: strengthening businesses in the age of Generation Alpha and in a world of digital dependencies 45 minute keynote speech for an audience of 300 business managers. Event Page https://fclugano.com/en/news/handelszeitung-business-and-football-summit-2026-aperte-le-iscrizioni
2026
Keynote Speech, By Invitation
Resilient into the future: strengthening businesses in the age of Generation Alpha and in a world of digital dependencies
45 minute keynote speech for an audience of 300 business managers.
boll-2026 4 May 2026 3 4–6 May 2026 Berlin, Germany Doctoral Seminar, Heinrich-Böll-Stiftung User Choice under Digital Platform Interoperability – Lessons from the Mastodon Social Network Digital platform interoperability enables users to interact across competing platform providers, like in e-mail or telephone networks. This is a widely proposed remedy to digital platforms’ extraordinary power and already entering legislation (e.g., EU Digital Markets Act). My thesis provides the first empirical evaluation of whether interoperability delivers on its theoretical promises, building on a novel dataset collected from the interoperable Mastodon social network.
2026
Doctoral Seminar, Heinrich-Böll-Stiftung
User Choice under Digital Platform Interoperability – Lessons from the Mastodon Social Network
Abstract
Digital platform interoperability enables users to interact across competing platform providers, like in e-mail or telephone networks. This is a widely proposed remedy to digital platforms’ extraordinary power and already entering legislation (e.g., EU Digital Markets Act). My thesis provides the first empirical evaluation of whether interoperability delivers on its theoretical promises, building on a novel dataset collected from the interoperable Mastodon social network.
diesl-annual-2026 14 Apr 2026 2 14–15 April 2026 University of Oxford, UK Digital Economic Security Lab – Annual Seminar 2026 Digital Platform Interoperability Event Blog https://diesl.eu/diesl-annual-seminar-2026-oxford/
2026
asm-2026 13 Mar 2026 13 March 2026 Online ASM Reading and Writing Group Does Digital Platform Interoperability Deliver on Its Expectations? Evidence from User Switching on Mastodon Discussion and feedback on the linked working paper (version 1 from 02/2026). Group Page https://www.socialmediaalternatives.org/index.html Paper https://osf.io/preprints/socarxiv/6wsrq
2026
ASM Reading and Writing Group
Does Digital Platform Interoperability Deliver on Its Expectations? Evidence from User Switching on Mastodon
Discussion and feedback on the linked working paper (version 1 from 02/2026).
diesl-2025 2 Dec 2025 2 December 2025 Online Oxford-Aalto Digital Economic Security Seminar (DIESS) Does Digital Platform Interoperability Deliver on Its Promises? An Empirical Test of Theory Users of digital platforms (e.g., X, Instagram, TikTok) have little choice but to accept providers’ conduct or forgo participation. Digital platform interoperability is widely proposed as a remedy to reduce the economic and political power of centralised digital platforms by enabling user choice without sacrificing network connectivity. Despite its prominence in policy debates (e.g., EU’s Digital Markets Act, Art. 7), theoretical claims on its effects remain largely untested. This paper evaluates three theoretical expectations on platform interoperability: that it neutralises proprietary network effects; it facilitates individual user choice and switching; and that technical standardisation risks homogeneous services. To test these expectations, this study analyses user switches within the interoperable social platform Mastodon. It draws on an unobtrusive, qualitative analysis of 1,400 posts documenting why individuals switched their interoperable providers. My findings challenge and qualify both the theoretical hopes and concerns. I find that interoperability is necessary but, on its own, insufficient to achieve the intentions associated with policy proposals. I identify practical obstacles such as incomplete implementation, information costs, and persistent switching costs that preserve proprietary network effects and that hinder individual choice and switching. Further, I challenge the anticipation of service homogenisation: I identify avenues of vertical (e.g., quality) and horizontal (e.g., governance values) provider differentiation under interoperability. These avenues form an emerging research agenda on new dynamics between differentiated but interoperable platform providers. Event Page https://diesl.eu/digital-economic-security-seminar-fall-2025/
2025
Oxford-Aalto Digital Economic Security Seminar (DIESS)
Does Digital Platform Interoperability Deliver on Its Promises? An Empirical Test of Theory
Abstract
Users of digital platforms (e.g., X, Instagram, TikTok) have little choice but to accept providers’ conduct or forgo participation. Digital platform interoperability is widely proposed as a remedy to reduce the economic and political power of centralised digital platforms by enabling user choice without sacrificing network connectivity. Despite its prominence in policy debates (e.g., EU’s Digital Markets Act, Art. 7), theoretical claims on its effects remain largely untested. This paper evaluates three theoretical expectations on platform interoperability: that it neutralises proprietary network effects; it facilitates individual user choice and switching; and that technical standardisation risks homogeneous services. To test these expectations, this study analyses user switches within the interoperable social platform Mastodon. It draws on an unobtrusive, qualitative analysis of 1,400 posts documenting why individuals switched their interoperable providers. My findings challenge and qualify both the theoretical hopes and concerns. I find that interoperability is necessary but, on its own, insufficient to achieve the intentions associated with policy proposals. I identify practical obstacles such as incomplete implementation, information costs, and persistent switching costs that preserve proprietary network effects and that hinder individual choice and switching. Further, I challenge the anticipation of service homogenisation: I identify avenues of vertical (e.g., quality) and horizontal (e.g., governance values) provider differentiation under interoperability. These avenues form an emerging research agenda on new dynamics between differentiated but interoperable platform providers.
weizenbaum-2025 6 Nov 2025 6 November 2025 Online DigiMeet 2025 – Platform Governance & Power: Between control, ethics and societal dynamics Digital Platform Interoperability – Strengthening User Choice, Reducing Platform Power? Hosted by the Bavarian Research Institute for Digital Transformation (bidt), the Center for Advanced Internet Studies (CAIS), Leibniz Institute for Media Research – Hans Bredow Institute (HBI) and the Weizenbaum Institute (WI). Users of digital platforms (e.g., X, Instagram, TikTok) have little choice but to accept providers’ conduct or forgo partaking. Network effects produce winner-takes-all markets, concentrating platform power, and structurally locking-in users. Interoperability is widely proposed as a remedy, promising user choice without sacrificing network connectivity. While celebrated in theory and policy (e.g., EU’s Digital Markets Act, Art. 7), its effects remain underexplored empirically. This paper examines user choice in the interoperable social platform Mastodon, drawing on qualitative analysis of over 1,400 user posts from individuals who switched providers within the same network. It investigates how platforms differentiate under shared protocols and how users experience choosing and switching. Findings identify six main avenues of differentiation, including governance, moderation, technical features, and identity, while part of the same network. Switching costs persist, complicating the idea of frictionless choice. The study challenges the view of interoperability as a straightforward fix for platform power. Instead, it shows that user agency hinges less on technical constraints, but on how interoperability is institutionally and socially configured. These insights offer guidance for future configurations and policy iterations that aim to strengthen meaningful user choice. Event Page https://www.bidt.digital/veranstaltung/digimeet-2025-platform-governance-power-between-control-ethics-and-societal-dynamics/
2025
DigiMeet 2025 – Platform Governance & Power: Between control, ethics and societal dynamics
Digital Platform Interoperability – Strengthening User Choice, Reducing Platform Power?
Hosted by the Bavarian Research Institute for Digital Transformation (bidt), the Center for Advanced Internet Studies (CAIS), Leibniz Institute for Media Research – Hans Bredow Institute (HBI) and the Weizenbaum Institute (WI).
Abstract
Users of digital platforms (e.g., X, Instagram, TikTok) have little choice but to accept providers’ conduct or forgo partaking. Network effects produce winner-takes-all markets, concentrating platform power, and structurally locking-in users. Interoperability is widely proposed as a remedy, promising user choice without sacrificing network connectivity. While celebrated in theory and policy (e.g., EU’s Digital Markets Act, Art. 7), its effects remain underexplored empirically. This paper examines user choice in the interoperable social platform Mastodon, drawing on qualitative analysis of over 1,400 user posts from individuals who switched providers within the same network. It investigates how platforms differentiate under shared protocols and how users experience choosing and switching. Findings identify six main avenues of differentiation, including governance, moderation, technical features, and identity, while part of the same network. Switching costs persist, complicating the idea of frictionless choice. The study challenges the view of interoperability as a straightforward fix for platform power. Instead, it shows that user agency hinges less on technical constraints, but on how interoperability is institutionally and socially configured. These insights offer guidance for future configurations and policy iterations that aim to strengthen meaningful user choice.
sase-2025a 9 Jul 2025 3 9–11 July 2025 Montreal, Canada SASE Annual Meeting Why is Computation Centralising? An Economic Model Based on 50 Years of Data Co-authored with Vili Lehdonvirta. Conference Track: J - Digital Economy. Computation and data are increasingly concentrated in large data centres operated by cloud providers such as Amazon, Microsoft, and Google. This centralisation raises concerns over economic concentration, competitive fairness, and the inclusivity of cutting-edge innovations like frontier AI systems. The shift to cloud computing reverses the decentralisation of computational infrastructure that took place as a result of the 1980s personal computing revolution. In this study, we examine the socio-economic forces driving this “reverse personal computing revolution”. Historically, the evolution of computational centralisation has followed a U-shaped trajectory. The 1960s saw centralised mainframes driven by high hardware costs. In contrast, the 1980s personal computing revolution shifted computation to the edges, enabled by cheaper semiconductors. Recent advancements in connectivity, coupled with rising energy costs and climate concerns, have reversed this decentralisation trend, favouring centralised cloud computing. Economies of scale in data centres partially explain this shift, but cannot account for the historical oscillation between centralised and decentralised computing. This research asks how we can measure historical costs of computation, connectivity, and the degree of centralisation, and how the relative cost of computation to connectivity is related to the degree of compute centralisation. We propose a simple economic model explaining the structure of compute (de-)centralisation in society: when computation is relatively more expensive, there are incentives to centralise it; when connectivity is relatively more expensive, decentralisation prevails. The study contributes to the understanding of cloud concentration and offers an economic explanation of computational centralisation that goes beyond scale-economy arguments. It can inform policy debates on excessive concentration in digital infrastructure. Conference Page https://virtual.oxfordabstracts.com/event/37937/submission/854
2025
SASE Annual Meeting
Why is Computation Centralising? An Economic Model Based on 50 Years of Data
Co-authored with Vili Lehdonvirta. Conference Track: J - Digital Economy.
Abstract
Computation and data are increasingly concentrated in large data centres operated by cloud providers such as Amazon, Microsoft, and Google. This centralisation raises concerns over economic concentration, competitive fairness, and the inclusivity of cutting-edge innovations like frontier AI systems. The shift to cloud computing reverses the decentralisation of computational infrastructure that took place as a result of the 1980s personal computing revolution. In this study, we examine the socio-economic forces driving this “reverse personal computing revolution”.
Historically, the evolution of computational centralisation has followed a U-shaped trajectory. The 1960s saw centralised mainframes driven by high hardware costs. In contrast, the 1980s personal computing revolution shifted computation to the edges, enabled by cheaper semiconductors. Recent advancements in connectivity, coupled with rising energy costs and climate concerns, have reversed this decentralisation trend, favouring centralised cloud computing. Economies of scale in data centres partially explain this shift, but cannot account for the historical oscillation between centralised and decentralised computing.
This research asks how we can measure historical costs of computation, connectivity, and the degree of centralisation, and how the relative cost of computation to connectivity is related to the degree of compute centralisation. We propose a simple economic model explaining the structure of compute (de-)centralisation in society: when computation is relatively more expensive, there are incentives to centralise it; when connectivity is relatively more expensive, decentralisation prevails.
The study contributes to the understanding of cloud concentration and offers an economic explanation of computational centralisation that goes beyond scale-economy arguments. It can inform policy debates on excessive concentration in digital infrastructure.
sase-2025b 9 Jul 2025 3 9–11 July 2025 Montreal, Canada SASE Annual Meeting User Switching within Interoperable Digital Platforms — A Force for Decentralisation? Conference Track: J - Digital Economy. Users of mainstream, monopoly digital platforms have little choice: accepting the monopoly provider’s conduct or not partaking in a specific means of communication at all. Network effects cause winner-takes-all dynamics in digital platform markets, with users typically concentrating on one monopoly provider. Two mechanisms can technically enable the diversification of platform providers, restore users’ agency in their provider choice, and facilitate accountability of providers towards users. Under interoperability, users can freely choose their preferred platform provider and are still able to interact with users of other providers. In combination with account portability, users can change platform providers without losing their connections and without facing detrimental switching costs. While those mechanisms are praised in the theoretical literature and policymakers are implementing related mandates, there has been no empirical research on their actual implications for user behaviour. This article provides such an analysis based on a large-scale unobtrusive real-use dataset. The study asks how prevalent account migrations are within an interoperable platform network, what the macro-level migration network structure looks like, and how users’ personal networks are related to their migration decisions. It uses a dataset of 8,696 account migrations within the Mastodon platform network and examines both macro-level migration flows and micro-level migrant networks. The study refines theories of push and pull factors in online migrations under interoperability, where social ties remain technically available after migration. It offers empirical insight into account migrations under interoperability and aims to inform policy debates around interoperability and account portability. Conference Page https://virtual.oxfordabstracts.com/event/37937/submission/862
2025
SASE Annual Meeting
User Switching within Interoperable Digital Platforms — A Force for Decentralisation?
Conference Track: J - Digital Economy.
Abstract
Users of mainstream, monopoly digital platforms have little choice: accepting the monopoly provider’s conduct or not partaking in a specific means of communication at all. Network effects cause winner-takes-all dynamics in digital platform markets, with users typically concentrating on one monopoly provider.
Two mechanisms can technically enable the diversification of platform providers, restore users’ agency in their provider choice, and facilitate accountability of providers towards users. Under interoperability, users can freely choose their preferred platform provider and are still able to interact with users of other providers. In combination with account portability, users can change platform providers without losing their connections and without facing detrimental switching costs.
While those mechanisms are praised in the theoretical literature and policymakers are implementing related mandates, there has been no empirical research on their actual implications for user behaviour. This article provides such an analysis based on a large-scale unobtrusive real-use dataset.
The study asks how prevalent account migrations are within an interoperable platform network, what the macro-level migration network structure looks like, and how users’ personal networks are related to their migration decisions. It uses a dataset of 8,696 account migrations within the Mastodon platform network and examines both macro-level migration flows and micro-level migrant networks.
The study refines theories of push and pull factors in online migrations under interoperability, where social ties remain technically available after migration. It offers empirical insight into account migrations under interoperability and aims to inform policy debates around interoperability and account portability.
diesl-summer-2025 26 Jun 2025 26 June 2025 Helsinki, Finland Digital Economic Security Lab – Annual Seminar 2025 Same but Different? Avenues of Competition under Digital Platform Interoperability Event Blog https://diesl.eu/diesl-summer-seminar-2025/
2025
Digital Economic Security Lab – Annual Seminar 2025
Same but Different? Avenues of Competition under Digital Platform Interoperability
mastodon-2023 22 Jun 2023 22 June 2023 University of Warwick, UK Mastodon Research Symposium Interoperable Digital Platforms — A Remedy for Monopolists’ Power? Event Page https://warwick.ac.uk/fac/cross_fac/cdi/news-events/mastodon_research/
2023
Mastodon Research Symposium
Interoperable Digital Platforms — A Remedy for Monopolists’ Power?
pcdc-2023 1 Jun 2023 1 June 2023 Online Politics & Culture of Digital Capitalism (PCDC) Colloquium A Separation of Powers for Digital Platforms. Horizontal Interoperability and Vertical Separation in Federated Platform Ecosystems Invited presentation. Event Page https://pcdc.timoseidl.com/colloquium#philipp-riederle-24.03.2023
2023
Politics & Culture of Digital Capitalism (PCDC) Colloquium
A Separation of Powers for Digital Platforms. Horizontal Interoperability and Vertical Separation in Federated Platform Ecosystems
Invited presentation.
platform-2023 9 May 2023 9 May 2023 Online Oxford Platform Economy Seminar (PEIG) Federated Platforms: A Separation of Platform Powers through Interoperability and Vertical Disintegration? Digital platform monopolists have become unavoidable, global, and autocratic regimes. This digital imperialism is not a technological necessity: ‘Federated platforms’ (e.g., ActivityPub/Mastodon, Matrix) are fully-operational ecosystems offering a technologically decentralised alternative. In these networks, competencies are distributed across three (vertically separated) levels of protocol definition, software development, and instance operation. Each layer holds different scopes of governance and power. All end-users can interact within the same (interoperable) protocol ecosystem, allowing within-market competition among software developers and instance operators. Federated platforms are under-researched and offer a unique research site for the first empirical insight into the competition regulation measures ‘horizontal interoperability’ and ‘vertical separation’ in a multi-sided market context. As such, for my MSc+DPhil research at the Oxford Internet Institute, I am working on understanding the relationships between technical network architectures and their resulting economic power structures.
2023
Oxford Platform Economy Seminar (PEIG)
Federated Platforms: A Separation of Platform Powers through Interoperability and Vertical Disintegration?
Abstract
Digital platform monopolists have become unavoidable, global, and autocratic regimes. This digital imperialism is not a technological necessity: ‘Federated platforms’ (e.g., ActivityPub/Mastodon, Matrix) are fully-operational ecosystems offering a technologically decentralised alternative. In these networks, competencies are distributed across three (vertically separated) levels of protocol definition, software development, and instance operation. Each layer holds different scopes of governance and power. All end-users can interact within the same (interoperable) protocol ecosystem, allowing within-market competition among software developers and instance operators. Federated platforms are under-researched and offer a unique research site for the first empirical insight into the competition regulation measures ‘horizontal interoperability’ and ‘vertical separation’ in a multi-sided market context. As such, for my MSc+DPhil research at the Oxford Internet Institute, I am working on understanding the relationships between technical network architectures and their resulting economic power structures.
sase-2022 9 Jul 2022 9 July 2022 Amsterdam, Netherlands SASE Annual Meeting Digital Start-up Founders’ STEM and Non-STEM Higher Education as Signals in Venture Capital Funding Decisions Conference Page https://sase.org/events/2022-amsterdam/
2022
SASE Annual Meeting
Digital Start-up Founders’ STEM and Non-STEM Higher Education as Signals in Venture Capital Funding Decisions