The City of London's Police Intellectual Property Crime Unit (PIPCU) has begun replacing advertising on sites deemed to be "copyright infringing websites" with official warnings from the government informing visitors that the site is under criminal investigation, according to this Wired UK report. The sites receiving these warnings that replace their ads have been designated by the government as "hosting copyright-infringing content" and reported to the agency by rights holders.
After receiving a complaint, an official from PIPCU evaluates the site in question to determine if they are infringing on copyrighted material. After verifying the complaint, they contact the site owner and give them a chance to change their behavior. If they do not comply, PICPU can either get the site taken down or replace the site's ads with warnings from the government about copyright infringement.
In order to get PIPCU's ads onto sites infringing copyrights, the police have partnered with content verification company Project Sunblock. That company maintains a list of infringing websites and then makes sure that when one of their clients' advertisements are going to be delivered to one of those sites that the police banners are displayed instead.
This is the latest phase of what the City of London government calls Operation Creative, an initiative between the police and rights holders that is attempting to disrupt online piracy by targeting those sites that host infringing content.
Head of PIPCU Andy Fyfe says that disrupting these sites is important because many of them make money off advertising. He also says that this protects consumers:
"This work also helps us to protect consumers. When adverts from well-known brands appear on illegal websites, they lend them a look of legitimacy and inadvertently fool consumers into thinking the site is authentic."
Source: Wired UK