aperture 3

[nazi]

Faces makes it faster and easier to search thousands of photos for shots of a particular person.Find a face in a crowd.
Faces automatically detects faces in your photos. Once a face is detected and identified, Faces can recognize that face and then scan your entire library — or individual project to find others just like it. It can even find a specific face in group shots. The more you use Faces, the smarter and more accurate it gets, making it easier to find shots of a particular person.Put a name to the face.
When Faces shows you an unidentified face, simply type in the person’s name. When you export your final images, the name is embedded as a keyword.
Aperture takes Faces further.

[khat17]

http://store.apple.com/us/product/MB957?mco=MTY5NjUxNjY

Please provide links when you do stuff like this.

[Anubis]

I'm not sure the different levels of this technology but Pisaca has similar feature and I don't find it to be very accurate depending on the different positions that an individual may be standing or the amout of zoom or focus in a specific picture an individual would be classified as different persons but then again Pisaca is free and this is going to run one USD200 so I would expect the technology to be much much much more refine.