Developers have a lot to consider when creating mobile apps. Apps have to be engaging, interactive, and provide some value that will encourage users to throw at least a few dollars toward the developers. Now there are calls for a new consideration: minimize bandwidth demands.

As consumers embrace the many possibilities that wireless broadband is enabling, service providers are seeing alarming growth in the traffic their networks must support. This traffic has two components. One is the data itself, with things like video downloads ramping up bandwidth demands. The second component is signaling. In order to establish a connection to the network a mobile device must engage in an exchange of information with the servers (to ensure proper billing, among other reasons). This exchange must take place even if the mobile device simply wants a status update, such as to see if new mail is available.

To handle the emerging traffic overload, most service providers are turning to some form of usage-based billing. As a result, how efficiently an app utilizes its connectivity can have a direct impact on the consumer’s cost of using that app. Lean applications will cost less to run than gluttonous ones.

Some examples have already arisen showing how bad things could get. Early users of Windows Phone 7 were finding their devices were sending as much as 50 Mbytes per day without their knowledge. Investigation revealed it was a background routine that frequently reached out to the network to check a status flag so that the user would have an essentially immediate notification when messages arrived. The check was so frequent and inefficient that users could almost watch their data allocation steadily draining away.

Most apps are not so extreme in wasting bandwidth, but there has been no particular incentive for them to be highly efficient, either. That may change.

Google’s director of Android partnerships has hinted that there may be a metering function in development that would let users know how much bandwidth their apps are using. This would allow them to make choices in app selection to help keep down their data costs. It is the equivalent of these energy meters now coming available that show you just how much that microwave or heat lamp is costing you in electric charges. The idea of the metering function would be to “incentivize” developers and providers to put applications on a data diet.

It’s not going to happen soon, and if developers begin routinely optimizing their apps to minimize the traffic they generate, it may not happen at all. But if apps are sloppy in the way they use network resources such metering may appear, users will start paying attention, and market forces will make sure the “fat apps” get thrown to the wolves.