Whilst I've never used adSense much, this does corroborate with chatter in SEO/webmaster forums, especially around 2012.
The paragraph on G analytics is also very interesting, it never seems to line up with other tracking tools like Piwik.
The paragraph on G analytics is also very interesting, it never seems to line up with other tracking tools like Piwik.
I worked at a company who used WebTrends. Some of the their customers installed Google Analytics alongside Webtrends and then would complain that the numbers didn't match up between the two. Sometimes it wasn't close (+/- 10%) other times it was closer, but there was always a discrepancy between the two. Of course it looked since we used WebTrends, we were inflating the numbers, when in reality, it was the exact opposite.
When I read this part of the post, I could totally see them tweaking the GA numbers so they were lower.
GA is always going to show 'lower' numbers than straight logs in particular because of this.