If you're not expecting this, it can be a bit jarring, as explains:

I couldn't sleep this morning, so I schlepped down to the nearest Wifi cafe... plugged in my noise-canceling ear phones and dialed up Pandora. Before I'd even logged in, the site launched into one of my favorite Tom Waits songs, "Jockey Full of Bourbon," followed by songs from John Lee Hooker and . Bang bang bang, three of my top artists, just like that.

Coincidence? Nope. Pandora pulled my musical preferences from my public Facebook profile. I didn't ask it to. It just did. It was both cool and just the tiniest bit creepy.

This must be what Facebook was talking about when it last month. To wit:

In the proposed privacy policy, we've also explained the possibility of working with some partner websites that we pre-approve to offer a more personalized experience at the moment you visit the site. In such instances, we would only introduce this feature with a small, select group of partners and we would also offer new controls.