In the late 90s and early 2000s, a lot of people were hunting the best bonuses offered at poker and casino sites. They searched the web for bonuses with positive expectation and exploited as many deals as they could find - and there were hundreds of them. This was a lucrative business back then and the bonus hunters soon got the somewhat degrading name "bonus whores."
Bonus whoring is mostly connected with casino games. In roulette, for instance, it's easy to calculate the house edge and how much you are expected to lose on every spin. If you find a bonus that covers your expected loss, and even gives you a small expected profit, bonus whores will soon be there exploiting this mathematical advantage.
However, bonus deals offering +EV are not that common anymore and today bonus whores are aimlessly wandering around the web reminiscing about the good old days. Casinos simply can't afford to give away money.
Poker, on the other hand, is a different story. You can still find online poker codes giving you sizable bonuses for signing up and making a first deposit. While casino bonuses have become less valuable, poker bonuses are actually bigger today than they've ever been in online poker history.
The reason for this is simple: You can't calculate your expected loss or profit as accurately as in casino games. Your results depend on your skills as a card player, which are very hard to determine (if you haven't logged thousands of hours of play and then analyzed the figures.)
This isn't to say that you can't do bonus whoring in poker; in fact, since the bonus deals are so good right now, poker bonus whores have the great opportunity of moving their bankroll between sites and clearing bonus deals. If you're a losing player, well, the bonuses might not help you reach a profit; but if you break-even, or even lose just a little in the game, bonuses will definitely turn your bankroll numbers green.
So if you're new to the game or want to earn a little more money from your daily grind, make sure you always play towards a pending bonus. The money is there waiting to be handed out by the different poker sites, and if you're playing poker, you might as well grab a piece of it in the process.
They say that drugs, gambling and prostitution will never go away. Combine the last two and you just might make some money.