I was invited to try a site recently by another forumite. Being a list keeper (read: anal retentive in need of therapy), I really like the site after using it for a couple of weeks.
The site is http://www.goodreads.com/. On it: you can create a profile, set up lists of (ahem) good reads, write reviews, invite the like minded to be friends, start groups, and on and on ad nauseum. It is a great way to keep track of where your head’s been, and even where it’s going (I have a backlog list and a wish list…)