Stumbleupon can get your AdSense Account Banned
I know this sounds very hard to believe but it is a real fact and many webmasters that practice Stumbling had felt it. The wost thing about that is that most of them didn’t really realized what they were doing wrong as their visitors did not do any click frauds, and therefore there was no reason for their account to be banned. In reality Click Frauds are one of the many CPC frauds on the Internet.
The similarity in all banned from AdSense webmasters was that they all used massive stumbling as primary traffic source. Also and Google sent them email stating that they ban/terminate their accounts for invalid ad impressions, but didn’t explain what exactly that meant bu that, and actually I didn’t know also until I found one book on per-per-click marketing book where the I stumbled across the term invalid impressions fraud.
A large number of impressions, without the accompanying click on your ad - if you notice that there are a lot of impressions (views) of your advertising, this could indicate impression fraud. Impression fraud is artificial inflation of your ad impressions that may cause your ad click-through rates to drop below the Google minimum and your ad will be disabled. Until you realize this, your competitors have free reign to use your keywords, sometimes at bargain prices. As well, your relevancy ratings for search engines may drop as they record numerous impressions, but no interest shown via visits to your website, which could lead to a shutdown of your campaign.— source: Pay-Per-Click Search Engine Marketing Handbook
Most of the AdSense Publishers know that Stumblers generally don’t click on ads and this somehow generates very low CTR. Depending on the ads generated to your particular page and the number of AD units, you might get stuck in a situation where your CTR goes below the required minimum and therefore you’re unintentionally making impression fraud. In order to protect their publishers (actually to keep their ads active so that they continue to pay) AdSense might send you the “you’re banned” email that can get you in really bad situation.
If you do get this email, I strongly suggest that you contact AdSense and tell them that you will lower the number of your ad units and ask them to give you some test period where you can increase your CTR above the minimum. Actually most publisher are afraid to get banned for high CTR, but in this case having low CTR is also a big problem.
Also I strongly suggest that if you have very low CTR (lower than 1%) you should try to change/optimize your pages in order to show highly relative AdSense ads or lower the ad units so that you CTR can go higher. This is common need for more clicks, but still some type of content don’t really generate too many clickers and in this case we must artificially keep the CTR higher due to this impressions fraud problem.
Please note that I don’t really have that much experience with impressions frauds since all my websites have average CTR between 5%-30% and I never got below the 1% mark. If you know more on that topic, please consider sharing it with us and helping fellow webmasters.