There are reports in WebmasterWorld and Google AdSense Help forums of huge drops in the CTR and earnings for Google AdSense publishers on July 1st.

The responses from official Googlers, at least coming second hand from publishers, vary.

One said in response to one publisher that his “Click spam rate increased since June 30.” Another received a generic response about reporting in general saying:

The thing is, there is starting to be a lot of publishers complaining about the drop.

So either (1) the reports are buggy or delayed or (2) Google stepped up their filtering of spam?

Here is a chart from my AdSense account, note, I don’t make a lot of money from AdSense:

Forum discussion at WebmasterWorld and Google AdSense Help.