As WordAds sites likely saw, in September we began to report ad impressions together with your earnings. Previously, WordAds sites looked at their page views to make a rough calculation about how many ads they were serving.
Some sites have asked why WordAds does not serve ads on every page. We share your interest in running as many ads as possible, however, there are a few reasons we cannot.
1) Ad blockers. The number of ads blocked by ad blockers that site visitors have on their computers varies, but we have seen estimates that 20% of ad impressions are blocked by ad blockers.
2) Ads not viewed. Some site visitors might bounce from your site quickly after arriving. This will count as a page view for you but if they don’t scroll down to see an ad it won’t count as an ad view.
3) Normal ad server discrepancies. There is always a few percentage discrepancy between site stats and what the ad server counts. Usually your site stats are a bit higher.
4) Mobile phone impressions. WordAds serves ad impressions on many smart phones but there are other visits to sites that count as page views where we do not serve ads because the phone type does not accept ads.
5) Ad partners default to blanks. WordAds runs a ‘waterfall’ of ad partners from the highest payers to the lowest. If the lowest paying partner hits a cap on ads for your site they will stop running ads.
For WordAds sites, there is not much if anything you can do to increase the number of ads served, other than to get more traffic. It’s our job as the ad operations team to do our best to leverage ad partners to increase the fill rate of ads.