If not, there is a very good explanation at http://en.wikipedia.org/wiki/Web_2.0. Here are some main points:
- To some extent Web 2.0 is a buzzword, incorporating whatever is newly popular on the Web (such as tags and podcasts), and its meaning is still in flux.
- Web 1.0" often consisted of static HTML pages that were updated rarely, if at all. The more dynamic Web (sometimes labeled Web 1.5) where content management systems served dynamic HTML web pages were created on the fly from a content database that could more easily be changed. In both senses, so-called eyeballing was considered intrinsic to the Web experience. Proponents of the Web 2.0 approach believe that Web usage is increasingly oriented toward interaction and rudimentary social networks, which can serve content that exploits network effects with or without creating a visual, interactive web page.
- Some of the more well known Web 2.0 entities are Google Maps (technology provided by Google that powers many map based services), Flickr (Flickr is a digital photo sharing website and web services suite), del.icio.us (social bookmarking, social software web service for storing and sharing web bookmarks), dig (site where news stories and websites are submitted by users, and then promoted to the front page through a user-based ranking system), last.fm (Internet radio station and recommendation system), and Technorati (Internet search engine for searching blogs, competing with PubSub and IceRocket).