All of these sound great.  However, some seem more worth the effort than others. I think the following are most important:  embedding of works, improved search, and personal annotations.  The others sound like they would be difficult to get people to use, especially given that there are other places people do some of those things. I also think the polling idea is a neat one. I've been mulling over this issue myself a bit lately. It would be extremely informative and interesting!