BTT - online book cataloging

Well, I haven't answered in a long while but this one is up my alley:

Do you use any of the online book-cataloguing sites, like

Library Thing or Shelfari? Why or why not? (Or . . . do you have absolutely no idea what I’m talking to?? (grin))
If not an online catalog, do you use any other method to catalog your book collection? Excel spreadsheets, index cards, a notebook, anything?

I didn't like Shelfari (and I tried something else I didn't like as well) but I do use LibraryThing. I started using it to keep track of the books I read and listened to in 2007 so I basically use it as a catalog, I don't use it as a social tool. I don't post reviews or rate or tag my books. There's a new site, Bookbump that looks promising. I am waiting for them to come up with an application that allows me to import my library from another program (LibraryThing) so I don't have to enter them all by hand. Although most of my books come from the library I also use Bookmooch and Paperbackswap to get rid of books (mostly paperbacks my husband buys when traveling) that I don't want to keep.