Term-paper and essay-writing services join prostitutes, firearms dealers, and hacking sites in Google's forbidden-advertising zone, the company announced on Tuesday.

Academic paper-writing services, or "paper mills," will no longer be able to buy search terms in the Google AdWords program, and thus their ads will no longer pop up in the "sponsored links" sections of a Google search-results page. (Links to those sites could still be found among the results on the main part of the page, however.)