Better than facebook reminding you about an ex that you don't want to think about anymore... or rather, "that awkward moment when you go to send your ex who you're still friendly with a message... and find out you've been defriended... then keep seeing her name on your timeline commenting on mutual friends' posts." Really kills a buzz...
A friend of mine broke up with his chick after a 4 year deal. A few months later moved to Boulder Colorado for a job and to turn over a new leaf. His ex completely unaware of him moving, not only also moved to Boulder, but was one floor above him in the same building. They both signed leases within a couple days of each other and were stuck.