Back in the early nineties I had at least two stretches where I subscribed to AOL. I was fascinated by the "commercial internet" - the Internet in those days was fiercely anti-commercial. But I hated how it worked. Eventually the Web emerged and AOL began its slow march to irrelevance.
Today I heard a Gartner analyst describe Second Life as having a similar niche to that AOL held in 1993. Second Life has all the mindshare and is viewed by many as synonymous with 3D interactive virtual worlds. In other words, they are on to something really important, and they know how to promote the hell out of it, but I find it pretty awkward to try to do anything interesting in it, or to find anything interesting to do (not being a big fan of cyber gambling or cyber sex).
I do think Second Life will play an important historical role by being the first mass-market, non-gaming, 3D virtual platform, but in order for this kind of environment to be really useful it has a long long way to go. But then, I wouldn't want to use Mosaic v. 1.0 anymore either, or Gopher.