Have you ever noticed the covert ads in games? I'm sure you have. That's because Nintendo still does in-game advertising right!
Some ads aren't exactly hiding. It's a common practice in media. A company gives a developer and publisher a little money, an iconic item is put into a scene, and people get a constant reminder that the product exists while enjoying another product. It's invasive and annoying sometimes, but Nintendo is one developer that's doing it right.
With Nintendo, the in-game advertising is handled in such a way that it enhances the game. You want it there. You seek it out or are an active participant because even though it's trying to sell you on something, there's also something really great about it at the same time.
The Mario Kart 8 Mercedes-Benz promotion is a good example. Nintendo teamed up with the car company to put some of its vehicles in the game. To be specific, the GLA, 1950's SL Roadster, and 1930's Silver Arrow. All three were ridiculously out of place, since they looked realistic and the characters, well, don't. But once the free DLC was in, it actually ended up being hilarious to see characters like Wario and Link shoved into these cars. Nintendo and Mercedes-Benz were trying to sell something, but it was hilarious.
The Animal Crossing: New Leaf 7-Eleven set is another great example. Only distributed in Japan, this eleven furniture set let people turn a house in-game into a 7-Eleven. It was surprisingly great, and it's one of those situations where you wished the promotion would have carried over to other countries. It was brilliant too. Many of the items were such that they'd work with other furniture sets in the game, so people would want them. You'd actually have to visit a 7-Eleven to get them, though. It was a genius marketing ploy.
And now, we have another great idea upon us. Splatoon has Splatfests. People enjoy competing, because they get Super Sea Snails. These let you go to Spyke and add slots to equipment, or reroll the skills already on a hat, outfit, or pair of shoes. Also, it's fun to pick a side and fight it out, rising up to titles like "Cat Queen." This weekend is a Transformers-themed contest, with people tasked with fighting for the Autobots or Decepticons. Their Inklings even get to wear shirts with the characters on them for the event. It increases awareness of the Hasbro property and markets to people, but is so much fun that no one cares.
Take note, developers and publishers. This is how you put ads into your games. You don't make them interrupt the game. Instead, you make them part of the game. Turn them into something entertaining and fun. People will appreciate it, and even seek out events or items that are this sort of "special."