Two mobile marketing channels and techniques

One technique used more often in mobile marketing is "in-app display media advertising".
in my blog "Three web marketing techniques" we discussed about how advertising can be used to show your game to people, well in-app ones do exactly that inside another game. They are often showed to players after reaching a game over or when visiting an in-game store. This is often used so the game maker can profit from the ad to support their product and can be a good way to show off Your game to a different audience. If you really wanted to you could even contact the maker of the game and have a crossover where both of you share audiences and help both sides to gain audience growth.

A great tactic to use not only on mobile but in other stores is to use coupons and discounts.
An example being when a customer buys a game of yours, give them a free time-limited coupon for another game of yours or an affiliate.
This can make it feel like the buyer is getting a special deal for buying your game. Now I suggested a time limit as it gives a small amount of pressure to the buyer - if they got it and didn't use it, then eventually they could show up and say "but I have this voucher promising me..." - and You have to uphold that promise/offer. This is where the tricky side of coupons/vouchers comes in as by adding a time limit you are guaranteeing that deal will last till the end date - think of it like a contract.
Now I'm saying this is a mobile technique as yes other stores tend to do deals like this BUT most modern phones can use QR codes as a way to make these deals seem special and quick. QR codes can be used though a pc but you would need a QR code reader, whilst mobile devices tend to have these on them already, and easier to find in public / real-world areas.