"TestSwarm ended up being a very challenging project to get to an alpha state (and probably will be even more challenging to get to a final release state). Dealing with cross-browser incompatibilities, cross-domain test suite execution, and asynchronous, distributed, client execution has been more than enough to make for a surprisingly difficult project. It’s mostly written in PHP and uses MySQL as a back end (allowing it to run in virtually any environment). Patches will absolutely be appreciated. "

via http://ajaxian.com/archives/testswarm-crowdsource-your-continuous-tests-for-javascript