• Since 1990 member of GI (German Society of Informatics)
  since 2002 in new Special Interest Group Mensch&Computer (HCI)
• Since 2004 ACM SigCHI member 
• Since 1995 member of FIfF (Forum InformatikerInnen für Frieden und gesellschaftliche Verantwortung), the German sibling of CPSR.   (1997-2002 contact person for the regional working group of FIfF in Bremen)
• End 1999 - Nov. 2005 member of the board of chairs of FIfF-Vorstand (Vorstand)
• Since Feb 2007 member of FIfF scientific advisary board
  
• 2002 invited into the working group 'Responsibility' (Verantwortung) to update and rewrite the German Society of Informatics (GI e.V.) Ethical Guidelines (ethische Leitlinien) 
• October 2003: founding member of the informatics and ethics SIG of GI ("Informatik und Ethik")
• Spring 2008, founding member of new working group  "Be-Greifbare Interaktion in Gemischten Wirklichkeiten" in the MCI  SIG of the German society of Informatics GI (tangible interfaces in mixed realities) 
• associate chair for German working group  Be-Greifbare Interaktion in Gemischten Wirklichkeiten   (graspable interaction in mixed realities) 2008-2010
   
  
• Co-editor of www.tangint.org  (wiki on Tangibles) with Brygg Ullmer & Albrecht Schmidt (this is not being updated any more since about 2006 - there's just too much happening!)
• Initiator and list manager for TANGIBLE-INTERACTION@JISCMAIL.AC.UK  a news and announcement email list around tangibles
  

     Reviewing Experience and Conference Involvement 

• IRIS'24 - 24th Information Systems Research Seminar in Scandinavia, 2001 (Long Papers)
• Coop 2004 - Intern. Conf. on the Design of Cooperative Systems 
• CSCW 2004, 2008 + 2010 - ACM Conf. on Computer Supported Cooperative Work 
• E-CSCW 2007
  
• Reviewer for the Journal of Computer Supported Cooperative Work since 2006, 
• Journal of Computer-Mediated Communication, Interacting with Computers (since 2008), Personal and Ubiquitous Computing journal special issue on Tangibles and Children
  
• CHI  2005 (Work in Progress / Short Papers), 2006 + 2007 + 2008 + 2010 (Long Papers + CHI Notes)
• UbiComp 2005, 2007, 2008 + 2009 + 2010 - Ubiqutious Computing Conference, 
• OzCHI 2005 + 2006 (Australian Computer-Human Interaction Conference) (long + short papers)
• CHINZ 2006 – Design-oriented HCI, Christchurch NZ
• Tabletop 2007
• TEI 2010 Graduate Student Consortium
  
• ACM Designing Interactive Systems 2010 (DIS'10) , Create 2010
  
• 'Occasional' requested to review for Group 2005, ISMAR 2006, UIST 2009 + 2010, IDC 2010
  
  
• Program Committee membership for Workshops: 
  'Tangible Interaction in Collaborative Environments' (TICE 2006) at the 15th International IEEE Workshops on Enabling Technologies (WETICE 2006) and TICE 2007,
  'Intelligent Environments' 2005, Special Session on 'How to Interact with Virtual Environments',
  MEIS 'Mobile and Embedded Interactive Systems' at GI-Jahrestagung 2006 and 2008 (German society of Informatics conference), 
  'Mixed Realities und Be-greifbare Interfaces für Bildungsprozesse' workshop at GI-Jahrestagung 2007, 
  second international 'Physicality' workshop, Lancaster 2007, 
  'User Interface Description Languages for Next Generation User Interfaces' workshop at CHI 2008,
  'Whole Body Interaction' workshop at BritishHCI 2008.
  Mensch&Computer 2010 workshop 'Be-greifbare Interaktionen' 
  I did loose track of the workshops at some point...
  
  
• Technical Program Committee membership:
  Participatory Design Conference 2006 (PDC), PDC 2008, PDC 2010,  TEI 2008, TEI 2010, Mensch&Computer 2008 (German HCI-conference), Tabletop 2008, (re)Actor3  International Conference on Digital Live Art 2008, E-CSCW 2009 and MobileHCI 2009
  
• workshop chair for Participatory Design Conference 2006
  
• Program Chair for TEI 2007 (Tangible and Embedded Interaction), Baton Rouge, Louisiana (ACM DL proceedings)
• member of TEI steering committee
• AC for CHI 2009 on the "Interaction Using Specific Capabilities or Modalities" sub-committee
  


• Member of the organizing  committee for FIfF-Jahrestagung 2001  (annual FIfF conference) in Bremen (motto: "2001 - Odyssee in Cyberspace")
• Program committee for FIfF-Jahrestagung 2005 in Munich
  
• Co-organizer of workshop ‚Physicality’ (Equator & British HCI), 6+7 February 2006, Lancaster, UK
• conference organizing committee (conference scheduler) for CHINZ 2006, Christchurch NZ, 
• Co-organizer of international Shareable Interfaces Workshop 2007, Open University, UK with Paul Marshall and Yvonne Rogers
• Co-organizer of workshop 'Theorie- und Praxiswerkstatt Be-greifbare Interaktion' at Mensch&Computer 2008, Lübeck, 
• Co-organizer of Shareable Interfaces for Learning workshop, Brigthon 12+12.9.2008, with Amanda Harris, Nicola Yuill, Paul Marshall and Yvonne Rogers in the context of the ShareIT project
• Co-organizer of CHI 2009 workshop on Whole-Body Interaction   
• Co-organizer of SICSA workshop on Whole-Body Interaction (with Lynne Baillie and Steve Brewster) 5-6.11.2009