Facebook checks where you're logging in from

Here's something I didn't know: Facebook keeps track of where you normally log in from, and uses this information to increase the security of your account. If you try to log in from an unusual location (for you), you're asked to provide extra information, such as your birth date.

This was discovered by Ed Parsons, Google's Geospatial Technologist on a recent business trip to Uganda.

This is the same method as credit card companies use to detect fraudulent use for cards, and it's not a bad idea.