Spyware is malicious, but adware, from an IT support standpoint, is no picnic either. At least a few times a week I will get a call from an often cranky user complaining about system crashes and overall slowness of their workstation. They usually ask for either more memory or a new computer, not having the slightest idea why they think they need those things.
About 99.9% of the time, I immediately see a wide array of shopping toolbars, animated mouse pointers, and a plethora of other intrusive items on their machine. Of course, the user has no idea where they came from, but they’re happy again once their CPU usage isn’t at a nearly constant 80-plus percent.
So, spyware in the end does the most damage, but adware comes very close in my book, primarily because even though it’s completely visible, the average end user has no idea that it’s doing anything bad. They just like visiting the sites that distribute it.
Although I think there are currently better spy/adware removal tools than Microsoft Windows Defender, I am extremely happy that this program is integrated into all versions of Windows Vista.