OK, this is an Idea that's been mulling around in my head for a week or so. . .
Do you think that there is a need, or a "market" for a social network combining aspects of Facebook, (life sharing | getting to know people | the lighter side of life ) Twitter ( micro-blogging | status updates | link sharing | twitter.com ), and the various enterprises of 37signals (collaboration | contact management | file sharing | chat | 37signals.com )
Such a site could run on Elgg ( elgg.org ).