Just about every modern video game comes packaged with “achievements,” a system of digital rewards that pop up whenever a player completes a predetermined action. They’re often tied to completing a certain level or reaching a certain score (although they can be more hidden and complex than that) and serve as a form of bragging rights to add another level to gaming. Usually, they’re shared on online gamer profiles like the ones provided by OpenFeint or Apple’s Game Center.

Achievements show up everywhere nowadays, including on just about every game to be found on Android and Apple’s iOS platform. And while it’s not the first company to try to turn all those more or less imaginary achievements into something real, Kiip, a mobile advertising startup, does seem to have a potentially great idea about how to do it.

According to a TechCrunch story, Kiip hopes to turn achievements into advertising dollars, and so far, it’s having some success in doing so. The idea is to replace annoying banner ads in mobile games that generally get ignored by players, and instead focus on the moment in which a player snags an achievement by handing out rewards from the companies with which it has partnered. The idea is that Kiip can customize the offers to the player and when certain difficult achievements are earned, a coupon or offer will pop up momentarily.

Kiip, which is only about seven months old, claims it’s rolling out rewards on 15 unnamed games that account for about 12 million active users. It also has numerous partners including Sephora, Carl’s Jr., Sony Dash, Vitamin Water and Dr. Pepper.

Advertising through achievements in a way that actually engages players rather than putting information in front of their eyes is a great idea, and potentially could have some real legs given the mobile gaming sphere. Gamers are already plugging away at titles like Angry Birds, and whether they are purposely looking to earn achievements or not, they’re definitely pulling them down. Adding a coupon or an offer at those moments not only gives players a reward for doing something hard, it also validates their play — elevating it from “killing time,” in many cases, to a fun activity that can be worth something more.

Kiip isn’t revealing what games it currently has its ads worked into, since it wants players to discover the offers naturally, but as long as it finds a way to make sure the offers are relevant to the player, I can’t see it not being successful. A game that is free and also uses advertising to offer its players something, instead of just shoehorning a banner ad into the experience, comes off more as a win-win for the player than simple, strategic advertising.