Web 1.0: Only the View is available, the Model is completely missing. The computer can't interpret anything. The computer does what it is asked to do be right or wrong. No wonder the computers were called dumb terminals in the beginning.
Web 2.0: APIs are coming, Controllers give partial accesses to the Model. The computer starts to enjoy. We have the ability to participate in interactive discussion. Facebook, Orkut, Blooger etc are few to implement this. We have been given limited write access on Web. We have started to appreciate this and success of Wikipedia is an example of how much community has appreciated this concept. We are both producer and consumer. The traditional methodology of one producer many consumer does not hold good anymore. Everyone participates equally in the evolution and development of a concept (wikipedia), work (open source) or a process.
Web 3.0: The Model is largely opened, we are finally able to read and write the World Wide Database. The computer can't wait! We are given full access to write based on the access level we have. We are part of a big universe but still manage to keep our own little universe isolated and whenever we want we become part of the big picture. Its an intelligent me part of the We.
Check out my earlier post if you want to know what after Web 3.0
Until Next Time ... :)