I don't study, but I learn, yeah.
A pump and dump scheme is one where you buy a large portion of a very cheap company, then flood potential investors with recommendations to buy it, usually using the fact that it's already gone up (due to your buying) as a way to get more people to fall for it. They claim this company is going to be the biggest thing since standard oil or something. They advertise gains in the thousands or tens of thousands of percentual points, or more. This is the pump phase. Because so many people are being told to buy it, the stock goes up dramatically. They point to that as proof that they were right, and continue to pump it. When they decide they've reached the top of the pump phase, they quickly unload all their stock, this is the dump phase, then the stock plummets as everybody sees their gains evaporate and sells, but only after the scammers dumped theirs.
It's a fraudulent way to scam lots of money off of investors who are easily influenced by what they hear or read.
G4T didn't face any sanction, the SEC is now friends with Lebed and they allow him to run his schemes, he probably kicks back a fair amount to them. The SEC will only persecute honest brokers who are offering a better service than the big firms who pay them bribes and have their CEO's running the place, or writing the laws. Lebed is small by comparison, but because he is a fraudster, he doesn't pose a threat to the big firms. And he knows the way of the game and who you gotta shake hands with and give gifts to.