my Goodreads shelves looks like a good tracking site of what books have been read or you wish to read. You can create multiple shelves that books can be stored on, for example Sci-Fi, Reading and Read for a Terry Pratchett book. It looks books up pretty well by author or title but it had a couple of issues trying to match an ISBN number that I got from one of my books, but typing the title in worked fine (probably a different edition). It has a widget plugin for wordpress and an image or flash plugin for other blogging sites and a facebook application too. I’m using the image plugin to the left here as flash is annoying – especially if you use flashblock like me. By filling in more details about your location it will show you information about other groups in your area and also links to upcoming for book events – there is one author appearing in downtown Columbus soon.
There is an option to import books using a text file using ISBN numbers – I’m not sure how well that would integrate with a cuecat but I would imagine that people with a cuecat have already scanned their books into a database already.
Naturally RSS feeds abound for various types of book categories such as the books I am reading, that are on my shelves, authors etc.
If you give it a try, my username is Absoblogginlutely.