I finally decided to look into why I was getting duplicate searches from different IPs within my site search. Every time someone would search for something directly on my site within a few minutes another hit for the same search, but from a different IP, would occur. Via samspade.org I was able to quickly determine that the second IP was always the Googlebot. At first I thought it was indexing the mt-search.cgi and by default Movable Type was referencing the previous query but looking at my logs I found that in fact it was calling the exact search.
How could that be? Simple – I had added the AdSense link to my search page template. Apparently the Googlebot goes out every time an AdSense ad is displayed. Since Google’s terms of service say you can’t include the AdSense code on a search results screen it was an easy decision to turn it off.
Speaking of AdSense and things Google doesn’t want me to tell you – I’ve had my best day to date today, just shy of #DELETED#. In one day. I recently received a check from Amazon for $12.50 which was for like a year or so.
One day. Damn.
[UPDATE - Via http://www.webmasterworld.com/forum89/27.htm (found via my Google related articles link, you do use that, right?) I discovered that Google sends out the Googlebot only when the page isn't in its index. Clearly that's the reason Google doesn't want you including the code on search results - they don't want the Googlebots being over worked!]