Mostly they dump bucketloads of money into projects that disappear into blackholes, or morph into other products that are dubiously successful.

As far as talent goes, the Dodgeball founders left, Jaiku founders left, Panoramio, Blogger and Feedburner founders left. That's off the top of my head, there's probably a lot more.

Seems like an expensive and unreliable way to do bulk hires.