$80-100m is far far too cheap. I think face.com made a poor decision here. Facebook will now be able to develop a system that will be able to recognize faces in any future or past photos (obviously including the 100s of billions they already have) and to link that face to a name and a bunch of demographic data. 3-5 years down the line, this ability will be incredibly powerful (think Minority Report, HUD overlays etc).