I dislike it when business agreements are changed unilaterally. (Think of Darth Vader speaking with Lando Calrissian.) Terms of service at a web site with authenticated login is a business agreement. A bit off topic but the only thing I like about FB is that it looks like an interesting application platform for 3rd party developers.
Facebook's public-by-default behavior towards privacy is one of the main reasons I've deleted my account. It's stupid and malicious, and they only get away with it because most of their users don't know better.
This could be really unfair to startups, depending on how hard it is to become a "partner."<p>Like, it'd suck to have your more well-financed competition (who happens to be buying lots of ads on Facebook) get the ability to automatically link up your friends as soon as you visit their site.