A heads up from Mandrik on our support team:
I just received multiple tickets from users informing me they had funds stolen. They all linked to the same transaction, and these were all stolen from vanity addresses. When I asked for further details they all confirmed that they used the same site to generate the address.
Vanity address generator: bitcoinvanity(dot)appspot(dot)com [DO NOT use this site to generate a vanity address; your funds will be stolen]
Address that is piling up stolen funds from vanity addresses (multiple transactions so far): https://blockchain.info/address/17Hnusfws7KsofWyZcNgTZ2hrWPrKuQ2na
If you ever used this site, then I’d move funds out the generated vanity address ASAP!
-Mandrik, Blockchain.info User Experience Expert