WEb 2.0 basically stands for the newer Web Applications like user created content. Blogging, Social Networking and Community sites et al. Basically in Web 2.0 there is more of collaboration based work. Sites like Orkut, Myspace, Blogger, o3 ,YouTube all are coming under this category.
The user created content is a exciting new area where insted of the professionals the users themselves provide first hand entertainment material.