Google and other advertisement companies have decided that sites that host pirated content will not be able to take advantage of advertisements from larger companies. Sites that host pirated content have a lot of traffic and also generate a lot of money from the adverts on theirs sites.
A study at The University of Southern California found that Google and Yahoo are the largest ad networks found on pirated sites. This and other studies like this are what prompted Google to takes steps against allowing their ad networks to run on pirated sites.
Google’s VP presented this information when asked about it, “In 2012, we disabled ad serving to 46,000 sites for violating our policies on copyright infringing content, and shut down more than 82,000 accounts for attempting to advertise counterfeit goods,” she said. “Nearly 99% of our account suspensions were discovered through our own detection efforts and risk models.”