What is Rake?¹

Rake is the scaled commission fee taken by a cardroom operating a poker game. It is generally 5 to 10 percent of the pot in each poker hand, up to a predetermined maximum amount, but not only can this percentage be anything, there are other non-percentage ways for a casino to take the rake. Some cardrooms will not take a percentage rake in any community card poker game like Texas hold 'em when a hand does not have a flop. This is called "no flop, no drop".

Poker is a player-versus-player game, and the house does not wager against its players (unlike blackjack or roulette), so this fee is the principal mechanism to generate revenues.

It is primarily levied by an establishment that supplies the necessary services for the game to take place. In online poker it covers the various costs of operation such as support, software and personnel. In traditional brick and mortar casinos it is also used to cover the costs involved with providing a dealer (though in many places tips provide the bulk of a dealer's income) for the game, support staff (from servers to supervisors), use of gaming equipment, and the physical building in which the game takes place.

What is Rakeback?¹

Rakeback in cash games can be calculated using two different methods: dealt and contributed. The dealt method awards the same amount of rakeback to each player dealt into a hand, and the contributed method rewards players based on their actual contribution to the pot. In poker tournaments, rakeback is deducted from cardroom's entry fee.

As online poker becomes more mainstream online poker professionals have begun using rakeback as a means of increasing profits or cutting their losses. Depending upon the stakes the player is playing, how many tables they are playing at once, and the number of hours played daily, online poker pros can earn thousands of dollars in rakeback every month. The rakeback rate is also important as there is no industry standard rakeback percentage.

Currently supported sites:

Getpokerskills.com currently offers you a 30% rakeback deal trough PokerHeaven. You can apply for this deal by clicking the banner on the rigth side of the page and download the software from there. After having the software installed you can create an account and your rakeback deal is activated immediately and will be paid every 1st of the month directly on your account.
Note: You have to make sure that the software is not downloaded or installed on the computer you are using now. If it is, then please uninstall the software and download again. If you do not do that, you will receive no rakeback!

¹Source: http://en.wikipedia.org/wiki/Rake_(poker)