Ja.net Collaborate is a prototype social networking site for UK education. Meeting best practice, it describes itself with three verbs: find, share, organize. Predictably, one might ask whether this is a natural venue for participation. Given network-level services like Facebook or Delicious, or domain specific initiatives (such as those Nature is building: for a recent overview see Jon Udell's discussion with Timo Hannay) or institutional provision.
One cannot simply create community by fiat. It grows, sometimes in unlikely places. It will be interesting to see how Ja.net Collaborate fares.