I test eleven anti-spyware programs for their treatment of cookies from 50 advertising systems. I report my observations in full detail, along with analysis of notable detections. For example, I find that PC Tools Spyware Doctor detects the most cookies from within my sample (50%), while cookies from Advertising.com, Aquantive/Atlas, Casale Media, FastClick, and MediaPlex are most often detected (each detected by 8 of the 11 anti-spyware programs tested). Conversion-tracking cookies from Yahoo Overture are widely detected (6/11), but no anti-spyware programs detects the corresponding Google cookies, perhaps because Google's cookies use arbitrary names that are hard for scanners to identify. I conclude by reporting some anomalies observed in testing, and by suggesting privacy-protective practices that may nonetheless accommodate typical advertiser objectives.
The report is available here.