Around two years old now, Southwest's Ding proves that a BDA can make a huge impact on loyalty and sales without being pretty or all that usable. It's just a collection of buttons representing the categories of the website, with a text window showing customized, time-sensitive offers based on your registration preferences.

The application

The good

With only a small sliver of the overall airline market, Southwest's Ding has achieved:

• More than 1 million downloads.
  
• More than $60 million in sales per year from the BDA alone.
  
• Incredible loyalty: in an industry where loyalty is everything, 45 percent of Ding users are more likely to make a future purchase from Southwest.
  
• This is also a classic example of how powerful perceptions are. Ding is promoted as a constant low-fare searching device: exactly what price sensitive shoppers want to hear. But once they download the BDA, it's a perfect pivot-foot for these users to make clicking through to Southwest.com a habit. Being on the desktop eliminates all the competition Southwest would face in the browser. People are far more likely to start their browser session in a Southwest.com category than they are anywhere else.

The bad

• The "ding" itself. The sound is cute in a 30-second TV spot. But I'm not constantly traveling Southwest, and the dinging got old, fast. The ability to turn off the sound and just have a visual alert (that isn't constantly blinking at me) might keep more casual users leaning forward.
  
• The app is just barely integrated. Ding would do well to show car and hotel offers in its text window as well.
  
• It only gets as personal as my flight preferences. Throwing in weather for those destination cities, or even a flight tracker on the desktop app, would make the proposition of keeping Ding active on my desktop a lot more viable.

What you can take away

• Captivation is king. Feel free to design for attracting users on price. What you'll get by training users on your BDA, and your web interface, will keep them coming back regardless. This is especially true as your demographics hit 34- to 59-year-old users, who will stick with an interface they've been trained on rather than try something new, even if it's better.
  
• BDAs for travel and hospitality are like a 100,000-square foot candy store no one else has heard of. It amazes me that no one besides Southwest is making a splash here. Make reservations, see live mileage or loyalty account numbers at a glance. Nothing else out there will serve your loyal customers with more utility and convenience while at the same time keeping those users away from all your competition's ad space on a zillion sites.