I was trying to look up a book previously read by ds9 from our library website, but the library doesn't keep or allow access to previous checkouts.
They did suggest using librarything.com for recording your books. I had already starting doing this, having fun reviewing things, etc., at librarything, which I think is a cool site. I think it would work well for an older child too, if interested in keeping track of their books, ones they own, ones they've read, etc.