There really is no Web 2.0 or web 3.0. it is just a way to talk about the "NEW" things (software) available.
The web is just evolving, it is still a infant. Think about clothing, you don't call clothing from 4000 years ago clothing 1.0 and clothing today 4000.0 or even 2.0 do you? clothing has came a LONG way in that time frame and still has the same name, CLOTHING. clothing does however have different categories for styles which is what the web does and should be used.