A striking example of this is the refusal of TV stations to broadcast ads by Adbusters.

The company had intended to broadcast several humorous ads for its "Crack the Code" promotional contest, in which $1 million was given away.

Asked if television stations should be allowed to broadcast ads for contraceptives, 60 percent said "yes," 37 percent said "no," and 3 percent said "not sure."

Political analysts said today that, heartfelt or even feigned, Mr. Tsongas's reluctance to broadcast negative ads would serve him well politically.

Small shops and businesses that could not afford television commercials can now broadcast ads for as little as $10 a spot.

Therefore, they tend to broadcast music, ads and stories relating to culture.

There are at least 37,000 shops, offices and health clubs across the country that broadcast ads on TV screens, according to Profitable Channels.

Earlier methods consisted of suing file-sharing sites, broadcasting just-say-no ads, even gluing together the CD players sent to music critics to prevent piracy.

Under F.C.C. regulations, television stations must broadcast political ads.

That law affects all kinds of political activities, not just broadcast ads, at any time during the year, not just before an election.