New feature in Picasa 3.5 allows for facial recognition.  Is it a good idea?

[youtube]http://www.youtube.com/watch?v=26Ch2D9g8vg[/youtube]

I’m wondering where Google got this technology to find faces.

• Did they contact the Las Vegas mafia?
• Was this recovered from an alien spaceship?
• What are the potential problems with identifying people you’ve photographed and giving that information to Google through Picasa?

This is the first product from Google where I’m a bit suspicious and although I think Google is quite awesome, I’m worried about the privacy issues.