Smartphone apps – particularly for Android and iPhone – are the darlings of agency and marketer’s interactive marketing initiatives. I won’t go into a long list of why developing only for the Android and iPhone platforms is limiting the reach of your mobile initiative and will just let the graphic below speak for itself. By eyeballing the graphic, Android and iPhone subscribers equate to about 30 million U.S. mobile users. That’s leaving behind 262.8 million U.S. mobile users (approx. 90%) who won’t be able to view your shiny new smartphone app…via Engadget.