What is rakeback? I have heard the term thrown around a lot but having done some research, I can't really work out what it is.

Is it applicable on pokerstars? that's the site I use.

For every hand you play, you pay rake. It is automotatically substracted from every pot. Basically all sites want to encourage people play more. So they have programs, that if you play more you get part of the rake back.

PS does have this in form of FPPs and VPP. Just look on their site VIP programm and FPP.

You get rakeback by signing up to a new site via a rakeback affiliate.

The affiliate is paid some of your rake by the poker site as an incentive to find new players. The affiliate passes some of that rake to you as an incentive to sign up via them.

The key thing is that to get rakeback, you need to sign up via the affiliate. It's no good signing up directly and then trying to get rakeback at a later date.

Not all sites offer rakeback. Those that don't almost always have some kind of 'loyalty program' which is supposed to reward regular players.

Some sites which used to offer rakeback no longer do so. (I'm thinking PartyPoker. There will be others too.)

Pokerstars doesn't offer rakeback but as lapka said, they have their own loyalty program (which new players are automatically included in).

Some affiliates, instead of offering you rakeback might offer you some other incentive for signing up via them. (Free/discounted tracking software, for example.) If the poker site you're joining in this way offers rakeback, you'd be much better off finding an affiliate who will give you that rake. Long term that's going to be way more valuable than any piece of free software.)

Bottom line: if you're about to join a poker site where rakeback is possible, you'd be mad not to get rakeback. Lots of players joined sites when they were playing very low stakes, thinking rakeback wasn't important. As they moved up in stakes, not getting rakeback cost them a ton.