I'm quite hesitant about giving any third party access to my personal data, although Facebook clearly has a very accurate profile of me. However, OAuth seems quite cool if I ever were to do so on a more extensive level (for instance, I've never given facebook access to my gmail account for it to obtain my address book). <p>I'm not keen on OpenID though. At the moment if someone grabbed my facebook password I'd be understandably annoyed. But if someone grabbed my OpenID password, and I used that for lots of sites, I'd be devastated.