Demonstration of iPhoto '09's new Faces feature
Through iPhoto's interface, I uploaded the photo to Facebook.
Faces-tagged photo, uploaded to Facebook using iPhoto '09
The Faces tags are all there, but the system is not smart enough to know that I am Eric Cheng, or that there is a real Adam Tow in my Facebook friends list. Instead, it tags the image with anonymous labels "Eric Cheng" and "Adam Tow." This is not so useful. Also, iPhoto grays out the upload icons (all except for Email) in all screens other than thumbnail view. I wasted probably 10 minutes trying to figure out why I couldn't upload via Facebook, MobileMe, or Flickr.
Faces appears to be really accurate, and I'm impressed with the technology. I know that the next crop of digital cameras all pretty much have the next generation of face-recognition technology embedded; they will recognize individuals and allow you to overlay special icons or colors over specific people that are tagged through the camera's interface. It's going to be really fun until someone runs the algorithm on the entire web. Once you're tagged, it will no longer be possible to be anonymous simply by omitting your name in a photo's caption.