The already given online identity options are less the optimal: for instance according to my priorities I put my twitter account in the place of my linkedin account because I rank twitter a lot higher than linkedin:
http://sciencex2.org/en/user/13

So I suggest adding more identity options besides the existing Facebook, linkedin, webpage and my new candidates are twitter, friendfeed accounts in the first place. When I read Jerry Sheehan's thoughtful comments in the website redesign feedback thread http://sciencex2.org/en/node/35325 I saw his twitter account in his signature and instantly subscribed to it.

Anyhow: can you imagine some version of twitter within the X2 site somehow?

Attila