Why did you choose to open and maintain an LT account? Do you/did you use other online cataloging/social networking sites, like GoodReads or Shelfari? Do you use more than one? Are they different or do they serve different purposes?
I joined Librarything about 2 years ago. I must have been searching for something to help catalog my books. I don't know how else i would have found it. I actually just found something to catalog my movies as well (it's not as good as Librarything though) I think I probably found the website, squealed and sat down and started entering my books, it's totally my kind of thing.
I didn't find out about GoodReads or Shelfari probably until a year later (maybe they didn't exist then).
I tried GoodReads because my friend invited me, but it seemed too much like an application on facebook that I don't even like that much. It didn't seem worth it to me to maintain my Librarything account and that as well, I think I still have a profile there though.
I actually tried Shelfari a few weeks ago, since I could easily import my books from a excel file, but it didn't like a lot of the ones I had manually entered into Librarything. It also listed all my books as read, which is so not true. It was kind of a pain in the butt to go through and fix that. I'm not sure if I'll keep using that or not. The books do look pretty on the shelves though.
As I see it now, Librarything offers me what I need. Maybe if I feel like dorking it up and maintaining more I will but Librarything will always be my number one, I have a lifetime membership!