Yahoo & Server Log Files Do Not Line Up.
A client that I do organic seo for runs his own PPC campaign - focusing mostly on Google but also Yahoo and, to a lesser degree, MSN. Here's the issue(s) we've run into w/Yahoo. First issue - we have two of them! Yahoo, because of their auto-reply system, cannot seem to deal with two issues at a time. We had a huge spike in click-thrus in one day for a phrase that draws little traffic, which would indicate possible click fraud. More concerning, many of the click-thrus (usually 10 or more per phrase) were not showing up on our server logs.
After we finally got through a series of auto-replies we received an email from Yahoo that our money had been refunded for customer satisfaction purposes, but no reason was given for the searches not showing in the logs. Same thing happened a couple of weeks later, but this time we conference-called with a Yahoo Rep. We were again given a refund and told that we needed to add a no-cache tag <META HTTP-EQUIV="Pragma" CONTENT="no-cache" to the site - the idea being that results were being cached so that only one hit was represented in the log instead of 12. This made no sense to me as there was not even one instance of the search phrase in the logs to begin with.
We contacted our web host to inquire as to whether they knew of any reason that successful searches reported by Yahoo were not showing up in the logs. They could not think of any reason but said we should add the tag to at least rule out Yahoo's logic.
We added the tag and a couple of weeks later same thing. Multiple successful searches on 5 keyphrases, none of which showed up on our server logs. Further correspondence with Yahoo proved fruitless as they kept sending auto-replies dealing with the "click fraud" issue and would not even respond to the log file question. My client called a rep again and was basically told, "Oh well, no more refunds".
Any ideas or similar experiences? Our response has been to simply stop using Yahoo. Ironically our natural rankings have increased a lot in Yahoo over the past couple of months and we've always done well in Google so it hasn't hurt business anyway.