We've covered AdDuplex before, the unique app promotion system by Alan Mendelevich gives developers a quick way to get their app advertised without costing a cent. Now, Mendelevich has taken the system a bit further by adding a mixed-model to the bag, starting in June, that allows devs to make money off of their submissions:

You just specify that you want to monetize your app in the settings. You can choose what percentage of your exchange balance you want to monetize. The system will automatically serve commercial ads to your application up to the specified percentage of your impressions. All unsold inventory will return to your exchange balance and you’ll get free advertising for it as you do now.

Here is an example. Let’s say your current exchange ratio is 0.8 and you specify that you want to monetize up to 50% of your exchange balance. In this case, if you serve, say, 1000 impressions per day, 400 will go into the exchange program as before (you will get 400 impressions of your ad), 200 will go to AdDuplex and up to 400 will be filled with commercial ads. If, for example, there’s only enough commercial ad inventory to fill 300 of these spots the remaining 100 will go back into your exchange balance and you will get 500 impressions of your ad instead of 400.

Although we hate the maths, we do like the idea of devs profiting off of their creations and we're glad to see another option for them to take advantage of. You can read more on the whole option right here at the AdDuplex Blog.