I actually think the activist straw poll at the coming Take Back America conference will be an interesting exercise. In a nasty bit of availability bias, we often conflate the political opinions of activists with those of online activists, which is probably a mistake. TBA, which will have a lot of online activists, should also draw from the base more generally, and so it'll be interesting to see if there's a large discernible difference between enthusiasm for folks Edwards, Obama, and Clinton in that strawpoll as opposed to the DKos, MyDD, etc polls.
If you want to go to the conference, by the way, you can register here.