sellAring has announced the launch of its audio-based mobile ad network, which offers a way to monetise Android apps, with a version for other platforms due to follow.

sellAring provides an SDK for app developers to embed in their app. A user who installs the app enjoys it for free, in return for hearing a 10-second audio ad in the time it takes for anyone they call from their mobile to answer their phone. After the call has ended, they are presented with a call-to-action menu.

Inventory is sold on a CPC (cost-per-click) and CPM (cost-per-thousand) basis, with the CPM model based on the number of time an ad is heard, as opposed to seen. The call-to-action menu which is presented to the user after the phone conversation ends includes options such as ‘Call the advertiser’; ‘Receive info by email’; and ‘Receive info by SMS’. The platform can also support customised calls to action. Ads can be targeted by app type, behaviour, location, and time of day.