To be able to understand rakeback you need to understand rake. Simply put, online poker rake is a percentage taken from every pot with real money on gambling sites. Rake is one of the ways in which the house makes revenue in poker (the other being tournament fees) since players bet against each other and not the house itself. Rakeback is essentially the process of re-distributing those funds taken out, back to loyal players. Typical rakeback percentages are between 27%-30%, but some other poker sites offer up to 65% plus. Poker rooms have two ways of calculating your rake contribution: shared and contributed.
The shared method is where rake is divided equally among all players. If there are 10 players in and total rake is €1, each player would get 10c of rake. The contributed method is where players must contribute money to the pot to get assigned rake, which is then re-distributed proportionally. If you were to contribute €50 to a pot of €150 and the total rake was €3, you would be assigned €1. Online poker sites have different ways of giving incentive to their players. Some sites don’t offer rakeback but offer reward schemes or bonuses that might be more valuable to those who don't plan on playing many games.
Thanks to online poker, today players can play on multiple tables at the same time. Referred to as rakeback pros, these players were once sitting in on real poker tables when they realised that they could be making a lot more profit by playing simultaneous games online - thus paving way for a new wave of poker players worldwide. A rakeback pro's strategy goes against the classic poker strategy where the aim is to walk away with a massive profit from every game played. The ability to juggle playing in on dozens of tables simultaneously could add up to pretty big rakeback payouts at the end of the month.
It's okay if rakeback pros make a small loss or breaks even. The more hands you play, the more you can make. Even if you play relatively low stakes of 50c or €1 cash games, if you can hold 24 tables at a time and put in 5 or 6 hours of play a day, you could be looking at €7,000 a month in rakeback alone. It might not be an exciting way of playing the game or helpful in improving your poker strategy in the long run, but big rakeback payments at the end of the month tend to make up for it.