Always eager for more windmills, I just now tried five searches myself. Found there were usually three ads with each returned search; most of them animated, all of them silent, and none of them for Guitar Tricks.

Maybe the timing (early Sunday morning) wasn't right for the GT demographic? ;) But then, that doesn't explain the ad for New York Texas Toast croutons...

Beyond timing, maybe individual computer settings are a determinant for how ads play. That certainly comes into play on the Weather Channel site.