The AP reports that Facebook is in the process of rolling out some new login protection security features that seek to combat an unwanted user hacking into one's account. It's a specific problem but a serious one that needs to be addressed, so it's good they're getting to it now.
You can choose to be notified by email or text message if you're account has been logged in from a new computer or mobile device, for one thing. It might be annoying, but if your account isn't being abused, it should be annoying very rarely. Facebook is also "adding roadblocks" to suspicious actions like simultaneous logins from China and New York. In that case, it might ask you to confirm who you are by actually using the info already on your account, like correctly identifying tagged friends (which is actually kind of cool, if you ignore that a hacker will at least see a picture of your friends, even if it's the ultimate stumbling block to his taking over your account).
There'll be a log of all the times and places you've logged in, so you can make sure it was you doing the logging in every time.
Oddly, this system is "opt-in," meaning by default it's not enabled. You have to dig through Facebook's labyrinthine privacy settings to turn it on. This might be a mistake, given how complex and intimidating Facebook's privacy settings already are.
The new features have already started rolling out to some users and will continue to reach more and more users until the whole 400-million-strong network is covered.