South Africa, July 22 -- It sounds ridiculous if you've never tried it, but this viral trend is more popular than you might think. Just one app alone, FoodNeverComes, claims nearly 1 million "cravings satisfied" to date.Why would people bother spending time on apps or websites that are built to never deliver? Ultimately, it's all about getting a dopamine hit.It sounds like harmless fun, letting users "buy" food, clothes or other products with no real-world cost, since most of these apps are free to use. But even when an app or website costs you nothing, there are downsides to watch out for - including how your choices can help advertisers better target you in real life.

From South Korea to the world

FoodNeverComes is one example of a fr...