Pop-Up Irony

What is it about pop-up ads selling pop-up blocking software? Sure they demonstrate the need for the product, but in the way that keying your car demonstrates the need for a paint job. OK, not quite. But certainly they do sacrifice some good will by the tactic. The combination of Microsoft Anti-Spyware and the Google toolbar have kept me pretty clean, but when I'm out and about, I am distressed by the way the machines I see are all eaten up by spyware and adware.