Ok... but I won't log into these kind of FB-connected sites before seeing a demo of what it does and what it will do w/ my FB account & contacts. Needs a video or a sandbox or something.
It actually doesn't get anything but public info, which you can see in the permissions request page on Facebook. All it does is grab your name, profile photo and url. It doesn't even store anything in a database--it's all in-memory at the moment.
It can't do anything with your facebook account or contacts. It just gets your friends list as a list of facebook user ids, and your name and other public info.
EDIT: Despite the down votes, my statement is still perfectly true.