Jo, you'll get no argument from me on the importance of networks. And in some discipline areas I have absolutely the best community in the world to talk to and discuss things with. Also all of the above doesn't avoid the problem of needing to build communities.

What I was trying to get at here was a specific thing that I have noticed on many different services - that scientists seem to be using very different funcionality to do one specific thing - point at a URL and then aggregate a discussion about that. So you see the same thing happen on Twitter, Friendfeed, Nature Network, Science Blogs etc, often about the same item. I was wondering whether, as David Crotty has said many times that we are somehow missing the point about what precisely it is that we are trying to do.