Fad

Dude, have you seen the latest Troll Gun? We gotta get one!

A fad is a short-term obsession of the human mind that spreads like a plague through social media, marketing, and word of mouth. Sometimes, things just hit the right dopamine receptors at the right time, and the item of the fad is everywhere before you can even start to remember the last one. The favorite Fad (as far as corporations are concerned) are the one that moves some units, and that's the kind they spend the most time trying to spread.
But basically anything can be the subject of a Fad: a hairstyle, some phrase, clothing, toys, doing something weird and probably stupid. The only thing they have in common is a sudden surge in popularity that everyone tries to capitalize on before it burns itself out. More than a few corporations have run themselves into the ground by chasing fads but too late to the game.
Once a Fad gets going, Corps do whatever they can to keep the fires burning. Social media propaganda, mass marketing campaigns, internal corporate pressure on employees, emotional blackmail by celebrities as it starts to flag are all fair game - at least until their inventory runs out.
Sociologists, now sponsored by corporations, spend a lot of time investigating the mechanics of fads, how they interact with people and change societal pressures. More fun people think that Fads have an actual memetic aspect to it, like a self-sustaining virus of thinking that drives people to engage in its desired behavior.

Behind The Fad

Some market analysts suggest that there might be more behind fads than mere city-wide peer pressure and mania. The Esoteric Order of the Invisible Hand especially maintain that "The Market" and/or capitalism isn't just a economic system, but argue that its many different functions comes together to form what's essentially a form of consciousness.
In this line of thinking, Fads something like encouraged growth or spurt of adrenaline when whatevers going on isn't enough. Even more, it might mean that 'the system' (or whatever you want to call it) is working to defend itself and keep itself growing, expending, like some great beast or horrific cancer.
But it's probably alright. After all, trust the market.

Either way, it means profit for the corporations and isn't that really what matters?