Open source software security

Google Miscounting Page Hits

30 November -0001

So I have a script on my website that alerts me whenever a page request is made. This is a piece of PHP code that keeps a count of how many distinct requests were made throughout the course of the day. Today I noticed something *very* curious. When I queried the database storing the information for my hits for yesterday I came up with:

1204

Now this is _very_ interesting because when I log into Google Adsense and check I see over 1300 page impressions. How could they possibly be off by almost 1000 hits? What gives?

[Update 2/9/2007]

Mystery solved. It seems that Google is actually responsible for the majority of the hits. This is a curious phenomena, but it seems that whenever a page is called Google actually requests the page and ostensibly adjusts the Google Adsense content to match the page content. This leads to erroneous traffic reporting that can nearly double your traffic reports. Distilling your traffic down to distinct IP addresses helps to give a much clearer picture of your traffic.

Even looking only at distinct IP's you'll find Google Adsense recording fewer hit counts. This is likely because a certain amount of traffic is due to spiders and users with javascript disabled. The former is likely to drive more hits that aren't recorded by Google than the latter.

It is very interesting that Google doesn't disclose that by placing Google Ads on your page you'll nearly double your "traffic" but all due to Google crawls. This can lead to some very skewed analysis if you don't adjust to the up tic in Google activity on your page.