There are communities which explicitly state their intentions. A bit related - I've seen forums etc. where the community pumps stocks, crypto currencies, and w

There are communities which explicitly state their intentions. A bit related - I've seen forums etc. where the community pumps stocks, crypto currencies, and what not. Everyone knows what happening, and they're all in on it. One typical way is that some "stock guru" is selling spots for private chats / rooms, where they'll regularly announce "signals" - i.e hyping up some penny stock. The group members will obviously start purchasing shares / pumping the stock, and exit as soon as outside buyers enter the cycle. Sometimes they just flat-out announce public pumping schemes on forums / user groups.