I know that this is a rather open type of question. You can answer it spontaneoulsy or by thinking about what is unique about web video in separation to other media.
Well, we are far away from any canonic categorization of online video, so just name genres that come to your mind. I will publish the list of all suggestion and try to add some structuring thoughts to it!
Any ressource is highly appreciated! Of course, I will publish all definitions on my blog.
If so leave your name and email adress, I will keep you updated on my progress.