There is an update of the Windows Picasa application. It seems overall faster, and adds as main feature Face Detection. After a lengthy scanning process (after all, I have more than 25K pictures on my HDD) it finds a lot of people, more than 10,000 faces in my case. It is somewhat tedious to attach names to all of them, perhaps this is a winter evening task. Once a person is identified, Picasa matches other pictures of that person. The accuracy is mixed: there are some strange failures, but also some great matches. Most funny to me: Picasa correctly identified myself in my Vulcan outfit. Ears and hair does not seem to be a parameter.