Even if you and your team of lawyers pore through Facebook's privacy settings every day to see what's changed, and you diligently monitor your settings to make sure you're only sharing what you want to share, your content is only as secure as your connection, and most people browse Facebook over an unencrypted HTTP connection, meaning anyone who shares the same network as you may be able to sniff our your traffic, getting access to your password, and hence everything else.
The New York Times' Gadgetwise blog reports that Facebook has added an option to let you browse the site over HTTPS, which means your surfing will be secure.
Anybody who uses Facebook should turn this on. Go to Account > Account Settings > Account Security to find the setting. Also, change your password: it's bad.
This has a been a public service announcement.