Bandwagon Technique

"100,000 lemmings cannot be wrong."

- an old proverb

"Eat shit, billions of flies cannot be wrong."

- a newer proverb

One of The Oldest Tricks in The Book: '''Everybody is doing it. You should do it too.'''

In other words, everybody is buying our product, so you should buy it too. Sometimes uses statistics to back up the claim with numbers. A form of Appeal to Popularity.

If a commercial tells you, "No wonder six million customers purchased our product last year," they're resorting to the Bandwagon Technique. Same for ads that boast of their product being "number 1"; if such ads appear during sports events, expect the appearance of foam fingers to make the point.

See also Pitch Mob. Often requires a little Lies, Damned Lies, and Statistics to pull off. The polar opposite of The Man Is Sticking It to the Man.

Anime

 * Exaggerated, in Fushigiboshi no Futagohime wherein the Big Bad is able to take over most of the world simply by telling the rulers of every kingdom that other countries had already surrendered to him. (None of the rulers are actually smart enough to check whether his claims are true or not).

Film

 * Any time a movie is advertised as "The #1 movie in America!" Or, if it's not the highest-grossing movie overall of the past week, "The #1 [insert genre] movie in America!"
 * This happens in Canada, too. For every damn movie. It's completely meaningless because you know the worst movie of the year will be hailed as the best one in the country. Hilariously, this will often be claimed by two movies at the same time.

Food and Drink

 * The famous McDonald's billboards displaying how many hamburgers the restaurants have sold. Mocked by Jerry Seinfeld: "How insecure is this company? Eleven billion sold... all right, I'll have one."
 * Parodied in mid to late '90s Snapple ads, where they would brag about being, collectively, the #3 drink (behind, it was hinted but never outright stated, Coke and Pepsi), because "unlike 1 and 2, 3 knows that not everyone likes the same thing" (that is to say, this is why Snapple has multiple flavors).

Gaming

 * Blizzard brags about World of Warcraft's 11 million+ subscribers.

Literature

 * Anything marketed as a "New York Times Bestseller", judging by the frequency with which books that aren't any good apparently get massive sales.
 * As David Brock exposed in The Republican Noise Machine, a common tactic of Republican operatives, dating back to the Nixon administration, was to buy books in bulk specifically so they would get on the NYT Bestseller list. First of these was a 1971 book called The News Twisters, a book that purported that the news media was slanted in favor of McGovern and against Nixon (and to a lesser extent, third-party George Wallace). It didn't matter that the book's methodology was spurious at best; the fact that it became a bestseller attracted wide attention before it was debunked. The same tactic has been applied to books by Ann Coulter and other contemporary right-wing authors, to similar success.
 * To be fair, it's not just a Republican thing: the Religion That Shall Not Be Named But Hail Xenu! did the same thing with L. Ron Hubbard's novels.
 * And the Valley of the Dolls author figured out which stores in the New York area the NYT was using for their sample, and bought them in bulk, according to a TV Movie about her.

Music

 * The 1959 album title 50,000,000 Elvis Fans Can't Be Wrong: Elvis' Golden Records, Vol. 2.

Technology

 * Cell phone commercials are notorious for this. Each carrier carefully devises some supposedly statistical reason why they're better than every competitor without actually resorting to using the same false statistical reasons as said competitors. "America's largest network," or "No wonder so many people choose our network," or "America's fastest growing network" are a couple of common ones.
 * America Online used to do this in its commercials a lot: "So easy to use, no wonder it's #1!" (To which anyone who'd actually used said services compared with normal online service would snark, "As in pisstastic.")
 * To be noted in this example and others listed that many times technology-related service providers are often #1 because they are in Many places the sole provider of such service. This is especially significant in the USA because the technological backbone anywhere outside urban centers is very archaic and dated legislation often causes providers to have a monopoly in an area.
 * Just about every online dating service claims to be the "#1 most subscribed to dating service."

Live Action TV

 * In Star Trek: Deep Space Nine, the Dominion win their allies this way. They even try this argument on the Federation more than once. "Join us, everyone's doing it. Come on, it'll be fun..."

Other

 * Current marketing ploy for State Farm Insurance is to tell people to ask their neighbors how they like the service. The ads rarely say anything about how they're better then other insurance companies, just how many people are customers.
 * Flintstones vitamins: Ten million strong, and growing.
 * Peer pressure lives on this.