Apple’s iOS and Google’s Android have centralized app stores. Apple’s App Store has been the number one app marketplace in terms the number of apps available. Based on the statistics from mHealth Initiative Inc.,1 the number of m-health applications on Apple’s mobile platform was far greater than the numbers of m-health applications on other platforms by the end of 2009. According to a statistical analysis conducted by Gartner,2 Apple with its iOS led in the app market in the year of 2010. Gartner forecasted that iPad would reach 54.8 million units in 2011. IPad, as a new mobile platform in tablet form factor, evolved from iPhone and came with a larger screen, higher resolution, and larger onscreen keyboard. It has attracted health care practitioners’ attention since
it was released.