Ironically, we actually have a great source of training data available that people can contribute with minimal effort - the Facebook graph API! All we need is

Ironically, we actually have a great source of training data available that people can contribute with minimal effort - the Facebook graph API! All we need is someone to auth the app allowing the "view photos" and "view friends photos" permissions and then crawl all of them for photos with faces in them. The return gives us a pixel location for the center of the face and then you compare that against what the detector returns. Keep iterating on that for the millions of photos Facebook grants you and you should get Face.com-level accuracy fairly quickly!