Stocks that are popular for younger adults are typically 'meme' stocks due to their high volatility. Most of them are popular tech stocks with high sentiment like AMZN, TSLA, SNAP (lol), AMD, MU etc, best way to identify a meme stock is when people only talk about the product, and not a single mention of the (usually awful) financials. think AMD, WEED, spotify, tesla.
That's not to say that meme stocks are bad investments. A lot of meme stocks actually have good fundamentals but sometimes they are overvalued and people have a tendency to fomo when the stock rises and panic sell when it drops. Add options to that and you can get an idea as to why they are 'meme-y,' because impatient people lose money. If you just buy a stock like MU when it's dropped and hold, you can get amazing returns because once again, the fundamentals are mostly good. ~ Copypasta