This is a pretty funny social network, if you can call it that. Perhaps it is just a forum for people to share funny found notes on a global basis? Whatever, you should check it out for a good laugh. It is updated regularly .
Passive Aggressive Notes gets users from around the world to send in those “painfully polite and hilariously hostile writings from shared spaces the world over” A Dish Draft might help some of these people. [note: way, way ahead of its time…] I personally like the "dearest roommate" note.
If you liked this, you might also like Post Secret. It is certainly more serious in tone and definitely more artsy. PostSecret is an ongoing community art project where people mail in their secrets anonymously on one side of a postcard.