Library Thing is certainly a good way to keep track of the books you have read. Since I like to read series I made sure that I put which book in the series it is in the tag. I have just started inputting my books from the paper list that I keep but it will be nice not to have to refer to the paper list (as in find where I hid it) when I am recommending one of my series to a patron.
I am still trying to figure out if I can create another folder so I can list the books that I listen to in a separate folder. There is a place called collections but none of those mentioned mention audio books. Perhaps I will check into some of the other online places to catalog my books and see if they offer this option. I will keep looking but if anyone has an idea on how to do this could you let me know.
Here is the link to my Library Thing http://www.librarything.com/home/hokeypokey3501.
Personally, I see that it can have many uses as a way to keep the books you have read organized. It can also be used as a way to recommend books that you like to other patrons with your same tastes in books. System wide I am not sure how it could be used since it would require someone to keep it updated with whatever information you wanted to put in it.