The doctrine of channeling, applied to indecent speech in regulated media such as broadcast and the telephone flows from the Supreme Court's holding in Pacifica Foundation v. F.C.C. that such speech cannot be banned from the media, but may be pushed to a time and place where it is unlikely that minors will get access. For example, telephone channeling involves reverse blocking of dial-a-porn services and requiring them to bill the call to a user's credit card. Cable channeling involves reverse blocking, while broadcast TV and radio channel indecent speech by airing it only after 10 p.m.
"Reverse blocking" means requiring access providers (the cable or phone company) to block access to the information unless otherwise specifically requested in writing by the subscriber.
No court has yet announced how indecent speech may be channeled on the Internet (let alone confirmed the constitutionality of applying indecency laws to the Internet). Reverse blocking, time channeling and credit cards are all completely impractical for the Net. Self-rating systems, however, are a possible way to channel speech on the Net, when coupled with browsers that parents can set to screen out undesirable ratings.