"Have you done an iPhone app before...?"

We've been asked that a lot over recent months. Everyone wants an app, but are we all suffering app fatigue?

All told, apps have been installed billions of times on Facebook and the iPhone combined. Given this, it's not surprising that brands are going app crazy. When done right, it can be a good strategy. After all, the costs of producing an app are typically quite low and apps have the potential to drive significant exposure for the brand through one of the the most powerful means possible: brand integration.

Thanks to the developer programs that Facebook and Apple have created, thousands upon thousands of "applications" have been produced that enable Facebook users and iPhone owners to do everything from the important (track UPS shipments) to the trivial (throw virtual sheep).

Here are some examples of brands that have used apps to gain exposure:

• Burger King. The fast food chain's Whopper Sacrifice Facebook app, which rewarded users with a coupon for a free Whopper when they deleted 10 Facebook friends, was eventually shut down by Facebook but not before more than 230,000 users completed the task and Burger King received significant press.
  
• Audi. Want to take an Audi A4 for a test drive on your iPhone? Thanks to Audi's A4 Driving Challenge iPhone app, users can create a car, select a course and race away from the comfort of their own phone.
  
• Chanel. The famous fashion brand's brings the fashion show to the mobile phone with its iPhone app. Instead of offering up a game, Chanel uses its app to deliver content, including video, news, fashion information and a store locator.
  
• Sony Pictures. When it came time to promote a new movie called 30 Days Night, Sony Pictures took a different approach to apps. Instead of building its own app, it struck a deal with the owner of a popular Facebook app called Vampires and took rebranded the 30 Days Night app for 3 weeks. The results: exposure via the tens of millions of visits the app received during that period of time and 59,100 sweepstakes entries.

As with any campaign, app marketing should be thoughtful. Brand integration should be done tastefully and users need to be provided with real value. Given the number of apps out there to choose from and the risk of app fatigue, they also need to be given an incentive to keep using the app.

While not every app is a success story, given the massive number of consumers that are using them and the relatively small costs of creating and distributing apps, app marketing is certainly worth a look.