Reddit is curiosity's new playground. Whether you want to know what it's like to live on the space station or how it feels like to waz if you've got two penises, your question can be answered in minutes by someone with firsthand experience.

This week, a mystery that has baffled parents and advertisers for decades was finally answered: what do teenagers think is cool? Teenagers, and a fair few disgruntled grownups, posted their answers, and the best were upvoted by the community as a whole, rising to the top of the page. (I suppose it could have been 80-year-olds doing the upvoting, but it felt pretty legit.)

The headline news was that every teen, whether from the deep south or South Africa, is on Snapchat. While grownups quickly tired of another gimmicky app, teens say that this is their main social network, not least because it's the one place where parents can't snoop on their photos. The other big tech credibility-scorer is apparently to say "Facebook sucks". Clearly everyone's aunty sharing Upworthy posts about heartwarming penguins is taking a toll on the site's street cred.

After that, things were neatly split into two groups. First, things that teenagers still think are cool because they haven't grown out of them yet. These include: Abercrombie, Macklemore, EDM and various kinds of bracelets that represent your personality. As ever, then, a lot of teenagers aren't as cool as they think they are.

Then there's the weirder stuff that grownups really don't know about. Fashion bindis, briefly a trend here in 2011, are apparently massive, as is wearing your telephone around your neck. Ironic following of religions is big in Australia, whereas Posh Pua, a brand of bikinis, is massive among teen girls in beach towns. More generally, though, today's teens seemed more open-minded. "Nerds" and "being clever" both came in for praise, as did a surprisingly wide-ranging menu of drugs and alcohol.

Presumably, desperate brands will scour this for what the wicked-sick fresh new ting is. Some people suspiciously tried to raise the question of what makes something cool or popular. But teenagers just replied with what they always have – don't try and aim your stuff at us, we're just going to like what we're going to like. It was actually quite refreshing to learn that the basics of being a teen – getting wasted, crop tops and rap – haven't changed much in three decades.

The best bit was the slightly begrudging lessons from older teens, aimed at those just entering adolescence. One 15-year-old commented that "getting pissed drunk to the point of getting sick" was a big trend at her school, with the first to vomit congratulated after the party. But another poster responded with: "I feel like drinking till you puke isn't really seen as cool anymore" and got more upvotes. Fickle, fickle trends.