Every hand you play at an online poker site has rake taken from it. That is how the sites make their money. If you are playing much, you will realize that it is a huge amount of money. Fortunately, you can get some of that back. And the way to get the money back is to make an agreement with an affiliate before you sign up at the poker site. To emphasize how important this is, when I looked back thru my total results, something like 30% of the money I've won has come from the rakeback I've received. Or said a different way, rakeback has added +35% to my online earnings. It is just a huge amount of money.
Here's how it works. Since the amount taken out of play via the rake is large, the poker sites are always trying to bring in new players. The way they do that is by hiring people on a commission basis to bring in new players. These people are called affiliates. Since the poker sites only want to pay for new players that generate a lot of rake, they pay the affiliates a rebate based on the amount of rake that their players generate. To get players to sign up with them, affiliates offer the majority of the rebate back to the player.
Here's an example.
Player A signs up with PokerSiteA with no rakeback. He plays a bunch hands and pays $100 in a given month in rake. He never sees that money again.
Player B signs up with PokerSiteA after making arrangements with an affiliate. He plays a bunch of hands and pays $100 in a given month in rake. The site returns $25 to the affiliate, who then pays the player $22 of the $25.
The actual numbers in this example are made up; the specifics are determined based on how much you play in a month and what level you play at. But the numbers are roughly accurate, so...
Don't play another hand without having signed up at a site to get rakeback, or you're just throwing money away..
There are many good affiliates out there, and searching at 2+2 or on the internet should identify some providers for you.
To get a sense of exactly how much having Rake Back is worth to you, here is some of my own data below. You would interpret the chart as follows:
At the $3-6 level, you pay $0.208 cents per hand to play poker in the Party network. You'll pay $11.02 per table hour played, and earn $2.76 in rake back. That is worth 0.46 BBs per hour. The bolded column is what rake back is worth to your bankroll, per table hour. Note that 25% is toward the high end.
In all seriousness, don't play another hand without rake back or a bonus working for you.