Application developers are in an enviable position. With mobile application development and attached revenue blowing through the roof, all manner of deals are possible between carriers and developers. With so much choice, it’s a convoluted landscape to maneuver in.

The conceptual duel between proprietary (iPhone) and open (Droid) has a new gunslinger in town: Exclusivity.

Carriers are beginning to negotiate exclusive deals with app developers and gaining customer market share from them. For example, Microsoft recently announced a new Bing app for Android. It’s not available to all Android phone users, only the ones that use Verizon. AT&T, Sprint and T-Mobile Android customers are out of luck. The Bing app is being handled as an exclusive service for Verizon customers, which adds value to Verizon’s service.

How did this happen? Several of Verizon’s BlackBerrys have been running Bing as their default search app for a while, so it was simple to expand the basic conceptual relationship.

This is quite different from Google’s current Android model where Apps in the Android Market can run on any Android-compatible phone, regardless of carrier. This has been a cool way to do business, but as more carriers turn to exclusive deals with app developers (making exclusivity a compelling proposition), the Android model may begin to lose ground.

For now, any developer can turn on a filter in their app that will limit downloads of their app to consumers on a certain carrier. Most developers to date choose not to turn these filters on, leaving their app as open as possible for all users. However, deals like the one between Microsoft and Verizon show why some app makers may decide that exclusivity is the new buzzword in their revenue stream.