I Don't Know About Web 2.0
But I know Web 3.0 will be all about cleaning the crap on the Internet. The creation and aggregation of content is all well and good, but there is just too much crap out there. In a few years it will simply become impossible to find anything on line because of all the junk that's piled up. I'm talking about spam blogs, old newsgroup threads, pictures of you taking hits from a 9' bong, etc etc. The next revolution will be about identity and information control. If someone googles my name, I can only control what shows up if I created the content and I host it. If, however, my name was casually mentioned on an online publication, editorial in a school newspaper, etc. then I have no control over that information whatsoever. People will increasingly find this unacceptable.
If someone tags you in a photo on Facebook, you can remove the tag, but you can't remove the picture. The next Google will be a company that comes along and enables people to manage their online exposure without infringing on others' rights in the process. This might be a crazy idea, but it's what we need in order to "restart" the Internet. Just like Gmail has a "report spam" button, so, too, must our web browsers have the same.
The next level in electronic democracy is to enable vast pools of users to eradicate malicious content by the power of their votes. Although the current season of American Idol is making a strong case against the wisdom of the masses, it is still a problem that can be mediated by exceptional software. That's where the opportunity lies for the Google killer. Where Google takes pride in being neutral and unbiased in their search results, someone else will come along and promise the opposite. This will not happen in the next year, but I believe it's coming.