Can anyone think of other interesting or useful things to do with tags for a booklog?

I don't use tags much. For my booklog here, I make each entry a memory, with the description (http://www.livejournal.com/tools/memories.bml?keyword=all&user=kgbooklog&sortby=des) including the date read, title, and author; and the keywords (http://www.livejournal.com/tools/memories.bml?user=kgbooklog) be the author and copyright date. Over on Library Thing (http://www.librarything.com/catalog.php?view=kgaert), I use tags to mark which ones I haven't read (or didn't finish) and a hint about where the book is hiding.