Mobile systems are some of the fastest growing sectors of internet use, but ad revenue on mobile devices is only a very small part of the total for internet ads. People spend as much as 16 hours a day with a mobile device in use, but the screen is small, and ads are intrusive, so that’s one reason the market hasn’t taken off. Also, the devices are very fractured, and the rules change between devices, wireless providers, and operating systems. In addition, there are few shared protocols or standards.

Read the full article here:
The Mobile Advertising Ecosystem Explained – Business Insider