- A federal law, the Public Health Cigarette Smoking Act, banned the advertising of cigarettes on television and radio, effective January 2, 1971.Fun Fact! A 1967 FCC decision had required stations to air anti-smoking ads, and those ads continue to this day. As for the tobacco ads themselves, only a handful of them (most notably the Flintstones Winston cigarette ads) are widely available on the Internet, and others may be lost forever.
- The History Channel (back when it actually fit its name) once aired a documentary about tobacco ads featuring over a dozen of the cigarette commercials made during the first two decades of television. Somehow, that wasn't considered to have violated the law.
- A Burger King commercial featured a scientist chasing the The Burger King himself and shouting out "Stop that King. He's crazy!". It was pulled following legal threats by various mental healthcare groups, and hasn't aired since then. Supposedly, McDonald's may have also shared displeasure with the ad, but that was for a completely different reason (possibly the price it advertised in the commercial).
- Apple's famous "1984" commercial, which introduced the Macintosh. Originally shown as a Super Bowl Special, it was pulled from circulation following copyright infringement accusations from the George Orwell estate. That doesn't stop it from showing up in "Best Ads" compilations, though.
- The huge majority of commercials, however, will never be seen again after they end their run due to a lack of home video compilations. Commercials are only preserved by accident by people recording particular shows and not skipping the commercials, on top of that having enough interest in the commercial to save it in the case of digital recordings. In addition, commercials and promos are now getting pulled from video hosting sites like YouTube over copyright reasons, banishing said commercials back to Keep Circulating the Tapes status.
Missing Episode / Advertising
Advertisements are the #1 victims of this Trope. There are many reasons for advertisement pulling, most notably public outrage over something considered "in bad taste." Fortunately, some missing advertisements have survived over the years through VHS tapes and recordings, and as a result they are widely shown throughout the Internet. Otherwise, you're shit out of luck if you miss your favorite advertisement and want to see it again.