Considering the PCWorld review that came out in March:

Free Android Apps Packed with Ads are Major Battery Drains

...Researchers from Purdue University in collaboration with Microsoft claim that third-party advertising in free smartphone apps can be responsible for as much as 65 percent to 75 percent of an app's energy consumption...

Is there a best practice for integrating advert support into mobile applications, so as to not drain user battery too much?

...When you fire up Angry Birds on your Android phone, the researchers found that the core gaming component only consumes about 18 percent of total app energy. The biggest battery suck comes from the software powering third-party ads and analytics accounting for 45 percent of total app energy, according to the study...

Has anyone invoked better ways of keeping away from the "3G Tail", as the report puts it? Is it better/possible to download a large set of adverts that are cached for a few hours, and using them to populate your ad space, to avoid constant use of the Wi-Fi/3G radios?

Are there any best practices for the inclusion of adverts in mobile apps?