Ostensibly, mybitcoin.com was hacked.
https://www.mybitcoin.com/login/sign-in.php
I was promised 49% of my bitcoins deposited there. However, I accidentally entered my old Bitcoin address, and not a new receiving one and clicked submit. The site has no option to resend, or a contact email. It now says that my BTC have been sent. Perhaps I donated the rest of them to someone.
Personally, I doubt that mybitcoin.com was hacked. All in all, I am out $25 dollars.
http://bitcoineconomy.wordpress.com/2011/08/19/the-search-fo...
http://www.betabeat.com/2011/08/19/search-for-owners-of-mybi...
Oh well.