Web 2.0 is a marketing buzz word. I stopped looking for examples of web 2.0 sites and when all that I found were retreads of ideas that have been around since the tech bubble. Look at sites like Digg. At their most basic level they are just like the directory scripts of the late 1990s that allowed people to vote on the quality of the listings. Sites which got more votes were elevated in the listings. There used to be sites which allowed people to comment on the listings. But, add in some Web 2.0 hype and you have the internet's version of the "emperor's new clothes". There was a time when web 2.0 was supposed to mean a new generation of sites and technology. That would have automatically excluded wikis because they predate the term and which had their variants back in the old BBS days. That should have automatically excluded sites like Digg. Web 2.0 seems to be just a good way to bring venture capital back into websites. Web 1.0 was a flop . . . but Web 2.0 . . . that's the future. It also helps that people confuse Web 2.0 with the new, super high speed internet backbone being developed by researchers and the military.
After working for the military I would say definitely a hoax. The last time the military led anything in technology would have to be the DARPA project which was the foundation of the internet after that private companies have led the pack. I disagree. But now that Web 3.0 is around the corner check out this thread http://forums.digitalpoint.com/showthread.php?t=1966555 I explained the versions of the internet.