Enlarge (credit: Getty Images | Chris McGrath ) YouTube is putting third-party ad-blocking apps on notice. An ominous post on the official YouTube Community Help forum titled "Enforcement on Third Party Apps" says the company is "strengthening our enforcement on third-party apps that violate YouTube’s Terms of Service, specifically ad-blocking apps." Google would really like it if you all paid for YouTube Premium. YouTube has been coming down on third-party apps, which often enable YouTube ad blocking.