Roughly 75% of mobile app ads are just promoting other apps

Have a look at your smartphone apps. Notice anything peculiar about the ads? In the majority of cases, the only things they're advertising are ... other apps.

Estimates vary, but analysts say a significant majority of ads in mobile apps simply promote other apps. Karsten Weide, an analyst with IDC, pegs the total at between 60% and 75%; mobile ad company Fiksu says it's between 50% and 85%, depending on the time of year. What does all this mean for the future of the app business? If most of the advertising dollars are coming from within the industry, is this a bubble about to burst? Quite the opposite, industry experts say -- the numbers show app makers and advertisers simply haven't yet figured out how to tap this promising business.