Android apps monetization using, earning money with android app

Airpush is an mobile advertising network which serves ads to users using android Apps on their mobile phones.
If the Android application you are using is using airpush to monetize their apps, then the app users will view ads in the notifications window. They claim that they dont show annoying ads while the apps are running.
Airpush says that app developers can integrate airpush ads in to their android application but just adding an additional jar file to the app.
The ads are delivered using the android OS's alarm manager framework and cached for some time.
The ads can be enabled/ disabled by developers or the end user can also optout by using the optout option on Airpush website.
The claim that they give CPM rates of 3$ and more.
The developers can also define which set of users receive ads. This can be beneficial if you have both paid and free version of the apps.