Ahh, the wonderful world of information security in the United States, where the threat of litigation can keep holes open and spyware active. eWeek has had a couple of articles this week on this topic. In The Chaotic World of Defining Spyware they discuss issues that CA has with companies that are fighting being labeled as spyware. In Big Security Guns Should Aim Carefully at Adware, Spyware there's a discussion of Symantec's scoring system versus Microsoft's behavior-based approach documented in a recent white paper.
There is money to be made in spyware and the bottom-feeders that are using spyware and "adware" are going to be very aggressive at resisting being labeled as such. You can see this in the Microsoft white paper, where the targets are labeled "potentially unwanted software" rather than spyware.
It's all just semantics. When you install something on my PC that I don't explicitly want and ask for, you're a bad person and need to be dealt with harshly.