Kids used to trade them on the bus, at the lunch table, at recess, and that's basically how I got acquainted with them. I didn't know what you did with them other than collect them and pass them around, but I was not immune to having a couple kicking around at the bottom of my backpack just in case I ever had to learn. There was no choice, you had to keep a few on you just to say you were cool. I still never really got what they were, just that all the cool kids were into them. And the reason they were cool? Because they had cool pictures on them.
And I mean if you could think it, there was a Pog for it. They came in these endless series, with cartoons, tire rims, sports teams, sports balls, movies, bugs, Goosebumps, states, flags, aliens, planets, cars, Sonic the Hedgehog, Star Trek, crazy 8s, psychedelic stuff, trippy flowers, monsters, eyeballs, skulls, superheroes...anything and everything that could be rendered in glorious 90s neon. If you were into something, there was a Pog for it that would immediately make you cool for having it, and if you actually "won" the entire series of something, then you could consider yourself elite.
I had to picture that there was some kid somewhere who was sitting on a throne of these things, in a castle built out of stacks of these things, just kicking back, basking in the glory... some kid who was like, the Pog Master, who had somehow managed to land everyone's face down. That kid would've been the king of awesomeness. I wonder where that kid is these days.