Redditors bought a lot of gamestops stocks to make its value go up and make Wallstreet people lose money bc they expected the stock to go down instead of up losing billions of dollars
Basically having a stock means you own a bit of a respective company so in the case of gamestop a lot or reddit users bought a ton of stocks and make the price go up so if you bought one at 5 dollar and now it cost 120 you can sell your stock at that price and have a net of 115