As far as I’m concerned, web 2.0 is still in it’s really early stages, and the reason is because the data isn’t all owned yet.
The network-effects play is about how you get increasing returns by everybody using your stuff, which is really what Microsoft did on the PC. Here we see it again, where these are winner-takes-all games. The internet looks like an open platform in the beginning, but once somebody gets a lead, their service gets better fast enough, if they’ve harnessed all the right levers, until it becomes a real barrier to entry
More at wired.com