It’s not uncommon to hear stories of disgruntled AdSense publishers whose accounts have been permanently banned by Google either due to "non-compliance with AdSense policies" or for "posing a significant risk to AdWords advertisers."

The compliance issue is almost always related to content. For instance, if any particular website is centered around banned topics (like gambling or pornography), Google can disable AdSense serving for that website.

The next issue is more serious as it relates to "click fraud".  No one obviously has a clear understanding of how Google determines "invalid clicks" but such an activity can invite an AdSense ban for life. There’s an appeal process at Google but again it doesn’t guarantee that your AdSense account will be reinstated even if you provide all the required details (like web server logs).

Aaron Greenspan was another happy AdSense user until he received an email from Google saying that his account has been cancelled.

While going through our records recently, we found that your AdSense account has posed a significant risk to our AdWords advertisers. Since keeping your account in our publisher network may financially damage our advertisers in the future, we’ve decided to disable your AdSense account. 

Aaron writes in Huffington Post that his AdSense account was disabled without warning and he literally ran from pillar to post at Google trying to reach everyone from the AdSense Customer Service to the Legal Team to Google forums but with no success.

If an AdSense publisher’s account is disabled for invalid clicks, he is not entitled to any further payment from Google and all the current earnings are returned to the corresponding AdWords advertisers. The same happened to Aaron as he had made around $721 from AdSense but the payment was stopped after the account was disabled.

With literally no options left, Aaron made a final attempt and filed a civil lawsuit for $721.00 (the amount Google owed to him) saying that Google could not prove any wrongdoing and that Google’s fraud detection algorithm was imperfect. All he had to pay was $40 as the court fees for this lawsuit.

The AdSense account was disabled on December 9, 2008, he filed the lawsuit against Google on January 15, 2009 and on March 2, 2009, the judge delivered the following verdict:

I don’t think I have the power here in Palo Alto small claims court to make you reinstate his account, but I think you owe this young man $721. I think there might be money in Google’s treasury for that.

Google paid him all the "due" AdSense earnings along with the court fees though his account still stands cancelled.

I think a big reason why Google lost this case is because their lawyer couldn’t convince the judge about how "click fraud" was detected in first place. Google has good reasons to not disclose their fraud detection algorithms in public court cases but the fact that this decision went against Google could probably convince many more ex-AdSense users to follow the footsteps of Aaron.