What is Web 2.0? I read the article by Tim O'reilly and I have a general idea of what Web 2.0 is. On the basic level its kinda like Google. It not really a product that gets shelved in stores and something that must be bought every couple of years like a computer. Its defined by O'reilly as a service. You don't have to pay for Google, and Google updates itself on a regular basis.
But Web 2.0 is more than just Google. Web 2.0 also has the important factor of sharing. Users, who are now seen as co-producers instead of consumers, upload and comment on stuff. Its usually the users who are giving the material while a service is simply listing them for fast and easy findings. This is like Youtube. Users upload their Videos and other users can find them and comment on them. This concept of "sharing" is almost everywhere in the web nowadays. You got Facebook, which acts like a social meeting place but you also share videos, photos and comment on each other person. Sharing is a vital component of Web 2.0 because thats how it differentiate itself mainly from Web 1.0. Sharing also goes into the concept of open software.
Open software is vital to Web 2.0 because people can improve stuff and they usually do it in a mass numbers in which it gets refined pretty quickly. It is even suggested in the article that services like Google should make their software "hackable". It allows hackers to improve and experiment with the proven code to make something better or something entirely different.
Web 2.0 also ,I think, is something that is always getting better. Since people are sharing and improving stuff on the web, the web gets better. At the end of the article, O'reilly does state that just because something has any of the things he listed does not mean that it is automatically Web 2.0. It needs to excel in those things. I think in general this is what Web 2.0 is.