The gist of this article is the claim that Second Life failed because it doesn't fill a consumer need.  Brilliant -- welcome to 2007.  Actually, maybe 2003, since this is basically the same criticism that many of us had when Second Life launched (do we really need a Metaverse?) and the reason the more game-focused set of us always had a little trouble liking Second Life.  It seemed like a very cool tool that was not particularly fun to use.  Without a game mechanic that lended purpose to your presence on the platform, what Second Life offered seemed a lot like an avatar-populated uncurated 3-D art gallery.

Diary of a Second Life trainwreck