There are two types of buffs: Coin buffs and Cap buffs!
Coin buffs increases the rate of coins you earn while watching the stream! You can have up to 4 coin buffs active at any given time, and every coin buffs stack. Please note that the coin buffs only increase the amount of coins you earn per minute. They do not increase the amount of coins you can earn just for watching the stream.
Cap buffs can be used to increase the amount of coins you can earn for watching the stream. Without a cap buff you can only earn 5000 coins for watching and have to win coins and get trivia questions correct to get more than 5000. Adding a cap buff raises the limit of the amount of coins you can get while watching.