Something that has failed to mentioned in this thread is 'the web as a platform'.
In my opinion your website needs more than user submitted content to be considered 'web 2.0'. Without more interactive web applications (such as ones using AJAX) and those creating a more interactive environment with less waiting, your still in the 'web 1.0' world. Users don't want to be sitting around waiting for pages to load anymore. They want dynamic functionality that makes for a more interactive experience.
