Well, don't try it with Metafilter, the spreadsheet would be all bl

sorry

Interesting idea, but why would I provide a random website my Facebok credentials?

To be fair, you're not actually giving your Facebook username and password to the website. It pops up a window which goes to Facebook directly, Facebook tells you what permissions you're giving the application and lets you choose whether to agree.

If you change your mind, you can revoke permission later. (Account -> Privacy Settings -> Apps and websites).