Dear colleagues, Friday, April 1 is fast approaching. We look forward to receiving your extended abstract for the Organizations and Social Network Sites Workshop at the Communities and Technologies 2011 conference. We are seeking papers dealing with the many research topics raised by the increasing use of online social network sites and technologies in organizational settings. Workshop details can be found at our site: http://tc.msu.edu/orgsnsworkshop Details about the C&T 2011 meeting can be found at the conference web site: http://ct2011.urbaninformatics.net/ The workshop will be held on Thursday, June 30 in Brisbane, Australia. We will be working with the workshop paper authors to prepare submissions for a special issue of the Journal of Computer Mediated Communication on this topic. Extended abstracts of 1500 words can be submitted via email to Charles Steinfield (steinfie@msu.edu) or Marleen Huysman (m.h.huysman@vu.nl). Thanks and please forward to colleagues you know who are working on this area. Charles Steinfield Michigan State University Marleen Huysman VU University Amsterdam