The defendants allegedly used Twitter and Discord to promote stocks without disclosing alleged plans to sell once the prices rose.

Source: SEC, DOJ charge social media influencers in alleged $100 million fraud scheme

In a similar vein, FTX gave a lot of promotional money to various social media influencers who pushed cryptocurrency trading schemes.

In a different scam, a Hong Kong-based company was running a business called Established Titles, which purportedly sold 1 square foot of land parcels that gave the recipient the right to use a Lord or Lady title. The business was a scam; tiny land parcels could not be registered in your name and there was no such law granting landowners a Lord or Lady title. Youtuber Scott Shafer (and others) took them down. Many social media influencers accepted promotional payments from this firm to promote this scam.