Google Charging for Visits?

I saw some unusual activity in my AdWords account for March 2. Curious, I uploaded my log file for that date and passed it through a filter program I have that strips all activity except those that enter from an AdWords ad (all my ads are uniquely tagged, making this an easy test). For the single day of March 2, Google charged my account for a total of 133 clicks. My log files indicate 134 clicks for the same day (can’t explain this one count discrepancy, maybe me entering my web from my AdWords account once). Here’s the curious part, though: My logs indicate 13 clicks originating from several IP addresses: 66.249.71.73, .39, .37, .28 – All owned by Google. I assume that these are housekeeping activities on Google’s part, which I don’t mind. If I’m getting charged for them, I do. On the surface, that does seem to be the case. I suppose it’s possible that Google is clicking thru, incrementing the hit counter and not charging for it, but now my stats are messed up (10% Google housekeeping is a lot). Can anyone shed some more light on this?

Perhaps people who work at Google are researching future purchases from there? Remember that exact correlation between different log analysis programs never happens.

There is also some discrepancy, particularly with Google due to the large number of partners.

Thanks for the reply. You make a good point, although I doubt that anyone from Google would have use for our products. I use Google search results only, and no content providers. I guess this is more a curiousity than anything else. I posted the question just for the kind of insight you have already provided. Thanks again.