One thing I hated about myspace was that spammers began creating accounts sending messages about their products.
Facebook has done in my opinion a pretty good job of keeping spammers or at least reducing the amount of spam on the site.
They have announce that have added more security measures to their site. One of the features is if there are simultaneous logins from your location and lets say a different location from another part of the world it will notify you of the attempted hack. Keep in mind make sure you create password that is not as easy to crack by creating a password with upper and lower case letters with alpa characters. This way it will stop most wanna be hackers from gaining access to your website.
Anyway here is the article I found. Its good news for facebook users.
New security measures for facebook users.