Blocking Ads from Pages that Repeatedly Share False News | Facebook Newsroom

Also see Finally, Facebook no longer lets fake news sites advertise to you (Mashable)

"False news is harmful to our community. It makes the world less informed and erodes trust. At Facebook, we’re working to fight the spread of false news in three key areas:

• Disrupting the economic incentives to create false news; 

• Building new products to curb the spread of false news; and 

• Helping people make more informed decisions when they encounter false news. 

Today’s update helps to disrupt the economic incentives and curb the spread of false news, which is another step towards building a more informed community on Facebook."

Blocking Ads from Pages that Repeatedly Share False News | Facebook Newsroom