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 Band Wagon 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.
- Any time a movie is advertised as "The #1 movie in Country X!" Or, if it's not the highest-grossing movie overall of the past week, "The #1 [insert genre] movie in Country X!". Occasionally it seems as though it happens 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.
- In Stroker Ace, Clyde Torkle claims that everyone cheats a little as an excuse for the number of rule-breaking modifications Lugs finds on his car.
- 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).
- Pretty much every MMO ever brags about its number of subscribers. This one does have a bit of truth to it; after all, part of the draw to an MMO is its community, and an MMO that doesn't have much of a community is probably not going to be as fun as the alternative.
- 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.
- The Religion That Shall Not Be Named But Hail Xenu! did the same thing with L. Ron Hubbard's novels.
- Valley of the Dolls author Jacqueline Susann 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.
- Authors unions support have had their books purchased in bulk.
- The 1959 album title 50,000,000 Elvis Fans Can't Be Wrong: Elvis' Golden Records, Vol. 2.
- Apparently the "bulk-buy to rig the charts" trick is common enough that the organisation behind the official British Top 40 have explicitly made it grounds for being booted out of the charts altogether.
- 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 the competitors. "The country's largest network," or "No wonder so many people choose our network," or "The country's fastest growing network" are a couple of common ones.
- One of them shows coverage maps of their competitors and asks people to identify what they are. In the commercials, the people guess all sorts of weird things, before being presented with the company's coverage map and saying "It's a map of the United States". For the most part, the correct answer to the others would be "a map of the United States with the parts where anybody actually lives shaded in." That's not to say that wider coverage isn't unhelpful, such as if you're in the segments of America outside of large population centers, or if you travel a lot, but the majority of people will find large amounts of coverage unhelpful.
- 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 it 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." Justified Trope in this case; like any social media, as a dating service's subscriber base expands, its service gets objectively better, as there's a larger selection of people to choose from.
- 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..."
- One of the marketing ploys 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 than other insurance companies, just how many people are customers.
- They often say "People saved exty dollars by switching to Trope Co.!". This is misleading, because it SOUNDS like everybody saves... but if one is not going to be saving money, one won't switch.
- Flintstones vitamins' "Ten million strong, and growing" takes advantage of a Double Meaning to assert both the product's popularity and efficacy.
- Avis rent-a-car has always billed itself as '#2. We Try Harder'.
- A UK advert for "Caffeine Shampoo" combines this with Made in Country X and Germanic Efficiency. Apparently "last year it sold over 100 million bottles in Germany alone". That's the entire pitch. They don't actually tell you what it is or why you might want it... but 100 million Germans can't be wrong, right?
- News outlets with political bias often do this, highlighting when their favourite party is doing well in the polls and assuring the viewers that everyone hates the other party.
- Ads for the weight-loss supplement Lipozene went to great lengths to tell you how many bottles of pills they've already sold. They didn't go into nearly as much detail regarding how effective all those pills actually were.
- For the last few years the WWE had bombarded viewers with messages of this nature, stating that RAW is the longest running weekly show ever, claiming that the previous week's show got more viewers than three other sports events put together, or bragging that their superstars have the biggest Twitter following. The odd thing is that anyone who cares is presumably already watching the show, so the messages seem to serve little purpose other than to boast.
- In Sinfest, an in-universe example: Evil: Everybody's doin' it.
- Nodwick both uses and subverts this in the same story. After the villains convince everyone to use a new cuss word this way, the henchmen's union is able to put a stop to it by showing everyone that they like it. They proudly claim afterwards that their profession is so undesirable that they can kill any annoying fad in less than a week if people think they like it.