As far as "social networking" sites go, I quite like LibraryThing. You input a list of the books that you own (up to 200 on a free membership), and it automatically cross-references them with other users, along with a bunch of other features such as groups, discussion lists, reviews/ratings, automatic recommendations, etc. It's great for branching out and continuing one's education.
I uploaded my list and set up a reverse engineering group there. I hope to see more members, though I suspect it'll fizzle immediately.







