edit_g - 11:22 am on Jun 29, 2004 (gmt 0)

Good question, and one that I've asked a few Googlers in the past - the best answer I got was that none of the ads have a high enough CTR. But this flies in the face of the fact that I've refreshed a search 10 seconds after seeing this and the two top slots have been occupied once again.

I'm sure AWA or somebody else will be happy to jump in and clarify this.