Bitcoin Vanity Generation Website
This was a simple web front end to the vanitygen.exe program.
Link was: https://bitcoinvanity.appspot.com
The site was implicated in fraud whereby the tool which calculates the client's key from two parts was backdoored and the resulting keys were stolen. Its case stands as an example as to why web services which handle private keys should be treated with extreme caution, and better be avoided in most circumstances. It was subsequently taken offline.
It is unclear whether the backdoor was placed there by the site owner or an intruder.