Look beyond the spyware points. The spyware is just what Claria uses to get data into Gain, their ad system. Microsoft wants Gain, probably to integrate into MSN search, or to provide an adsense like system. Gain is very, very advanced. Did you all think they were going to pay $500 Million just for some spyware inside-info? I have more info here:

http://www.perfected.org/archives/2005/07/01/microsoft-to-buy-claria-you-might-think-they-are-crazy-but/