This is annoying, but good.
With over 4967 libraries around the world, LibraryThing isn't just a one-trick pony.
Choosing a source
Most LibraryThing users choose OverCat (our own internal books database) as their primary source, with Amazon.com and the Library of Congress a close second. Other libraries are chosen for their strength in a particular language or field of study.
For non-English books, the Library of Congress is often one of the better choices.
Choose a source
Choose a default source for adding books from other sites.