11 C.F.R. § 100.26
Public communication means a communication by means of any broadcast, cable, or satellite communication, newspaper, magazine, outdoor advertising facility, mass mailing, or telephone bank to the general public, or any other form of general public political advertising.The term general public political advertising shall not include communications over the internet, except for communications placed or promoted for a fee on another person's website, digital device, application, or advertising platform. A public communication is promoted for a fee where a payment is made to a website, digital device, application, or advertising platform in order to increase the circulation, prominence, or availability of the communication on that website, digital device, application, or advertising platform.
11 C.F.R. §100.26