I would think one could use Google Docs or add notes to a .pdf as a class reading together. This would be social reading on a small scale, not like LibraryThing where you are sharing your reading history with the world and comparing your library to other people’s.

Kindle now has shared highlighting – but to be honest, I find it creepy. Also, I haven’t met too many students who are excited about reading this way. They are bothered that they can’t share the texts themselves, which are not even really owned but licensed. Funny how Kindle enables one kind of shared reading experience (I can see what other people have highlighted) but not another (I can pass a book on to a friend).