Member of Adilkno, the Foundation for the Advancement of Illegal Knowledge, a free association of media-related intellectuals (Agentur Bilwet auf Deutsch). He is a radio program producer (for Radio Patapoe in Amsterdam and VPRO radio) and a co-founder of The Digital City, the Amsterdam-based Freenet and 'Press Now', the Dutch support campaign for independent media in Former Yugoslavia. Former editor of the media/art magazine Mediamatic (1989-1994). In 1991-1993 he lectured media theory in Bucharest and Budapest at the art academies there. Co-founder of the Amsterdam-based internet content providers desk.nl (culture/arts) and 'contrast.org' (politics) and a 'cultural ambassador' for Waag Society for Old and New Media. Regular contributor of Andere Sinema (Antwerpen) and member of the editorial board of ARKzin (Zagreb). In the spring of 1995, together with Pit Schultz, he founded the international nettime circle which is promoting 'net criticism'. In 2001 co-founded Fibreculture list.
Co-organized the Wetware Convention (Amsterdam, 1991), Next 5 Minutes, a international conference on public access and camcorder activism (Amsterdam, 1993), Ex Oriente Lux (Bucharest 1993), the first Romanian media/art event, MetaForum I/II/III (Budapest, 1994-6), Interface 3 (Hamburg, 1995) on the culture of computer networks, Next 5 Minutes II on 'tactical media' (Amsterdam, 1996). and moderated the (net) symposium of Ars Electronica 96 on 'memesis'. He was the project coordinator of the Hybrid WorkSpace, which took place during the Documenta X (1997) in Kassel. Later on co-organised Browser Day (Amsterdam, 1998-2002), Net.Congestion event (Amsterdam, 2000), and conferences such as Tulipomania DotCom (Amsterdam/Frankfurt, 2000), Dark Markets (Vienna, 2002), Networks, Art, & Collaboration (Buffalo, 2004), Incommunicado (Amsterdam, 2005), The Art and Politics of Netporn (Amsterdam, 2005), and New Network Theory (Amsterdam, 2007).
Among his publications are Adilkno's 'Empire of Images' (Amsterdam, 1985), 'Cracking the Movement' (Amsterdam, 1990/Berlin, 1991/New York, 1994) on the squatter movement in Amsterdam, 'Hoer zu oder Stirb' (Berlin, 1992) on free radio, 'Medien Archiv' (Amsterdam 1992/Mannheim 1993/New York 1997), 'Der Daten- dandy' (Amsterdam/Mannheim, 1994) and 'Elektronische Einsamkeit' (Köln, 1997)
In June 2004 founded Institute of Network Cultures in Amsterdam. In 2005-2006 he was a fellow at the Berlin Institute for Advanced Study (Wissenschaftskolleg zu Berlin), where he finished his third volume on critical Internet culture, Zero Comments (Routledge New York, 2007).
- Zero Comments, Blogging and Critical Internet Culture, Routledge, New York, 2007.
- The Principle of Notworking, Concepts in Critical Internet Culture, Amsterdam University Press, Amsterdam, 2005.
- My First Recession, Critical Internet Culture in Transition, V2-NAi, Rotterdam, 2003. 
- Uncanny Networks, In Dialogues with the Virtual Intelligentsia, MIT Press, Cambridge, 2002. 
- Dark Fiber, Tracking Critical Internet Culture, MIT Press, Cambridge, 2002. 
- Hör zu – oder stirb!, Edition ID – Archiv, Amsterdam and Berlin, 1992, (German).