As of this week, no more advertisements incorporating "sexually explicit content" will be promoted by Google's advertising network.

Google's AdWords platform is used to place advertisements on Google-owned sites; other sites can also choose to host AdWord ads on their own sites. The platform is thought to be responsible for the majority of Google's revenue, but although Google has placed restrictions on adult content for a while, the latest changes could potentially have chased some advertisers elsewhere.

According to CNBC, Google sent a message to advertisers at the beginning of June in order to notify them that it will no longer accept ads "that promote graphic depictions of sexual acts." It went on to say that this included content such as hardcore pornography and the depiction of masturbation and genital, anal, and oral sexual acts.

"When we make this change, Google will disapprove all ads and sites that are identified as being in violation of our revised policy. Our system identified your account as potentially affected by this policy change. We ask that you make any necessary changes to your ads and sites to comply so that your campaigns can continue to run," the message read.

Google first announced that the changes were coming in March, when it advised users of AdWords that it would be updating its adult sexual services, family status, and underage and non-consensual sex acts policy pages. As well as prohibiting sexually explicit content, it also took the opportunity to clarify its guidelines on other adult activities. Adverts for strip clubs, dating sites, and "non-intimate" massage services, for example, are still allowed, but are subject to tight restrictions regarding classification.

Some have speculated that the changes signal hard times ahead for the porn industry, as many companies such as PayPal, Amazon, and Chase Bank have started to disassociate themselves from clients who work in the adult entertainment industry. According to CNBC, 351 million Google searches were made including the words "sex," "porn," "free porn," and "porno" during the month of May, so these bigger changes from Google could potentially leave a lot of money on the table.