The Feb/Mar issue of Research Information features a story on the Web2.0 initiatives coming from the Nature Publishing Group to promote sharing and collaboration. It mentions:
- Connotea - the social bookmarking site
 - Scintilla - a current awareness tool
 - Dissect Medicine - a current awareness tool designed for medics
 - Nature Network - a social network for researchers
 - Nature Precedings - a service for publishing preprints and other grey literature, subject to review
 
NPG also has a page on Facebook and a presence in SecondLife. It would be interesting to get some info on the demographics of the users of these different services.