Bots account to 50% of online traffic and are a pesky problem to publishers. Fake bot traffic on the publisher sites generates dummy impressions that do not lead to any amount of clicks.The intent of bots will vary, ranging from data mining of the web to targeted attacks like web scraping. As bots generate page views/impressions and no clicks, they lead to a decline in the CTR (Click Through Rate).
This decline in CTR also reduces the Cost Per Click (CPC) as the value of the publisher site to the advertiser reduces. Reduction in CPC directly impacts the revenue generated by the publisher from online advertising. Consider this: Out of a 100000 page views if the clicks are only 2 then the CTR ( Clicks/Impressions) would be as low as 0.002%.This kind of CTR is low and will not serve any better in the long run.
Ad networks like Google Adsense are very careful in choosing the right kind of publishers under their umbrella. When Ad networks realize that a particular publisher is unable to generate the necessary clicks, they obviously become unattractive. In some cases involving bot traffic, it could be as worse as blacklisting the publisher.
Publishers at the end of the advertising funnel should employ a bot prevention solution that will block bots from creating dummy impressions and help improve the CPC. In our experience, website owners have reported a significant increase in revenues following deployment of bot prevention solution.
Rightfully anticipating the long-term increase in CTR and CPC with respect to the cost of the bot protection solution will enable publishers to understand the profitability involved and make the right decision.