In almost 2 months, it will be 4 years since the launch of the App Store, and by then the store will probably host 650.000 applications for iDevices. In 4 years the App Store grew extremely much, being the largest virtual application store in the world. Last year it was said that Google Play will surpass it, but Apple took care to publish everything crap interesting applications in it and for now it maintains its title. In 4 years, the App Store has collected almost 25 billion downloads from over 300 million iDevices and the number increases by over 10 billion downloads annually.
If we are to make a separation of the applications available there, then 400.000 of the applications are made for the iPhone/iPod Touch and 200.000 of them are made specifically for the iPad or are universal, but Apple tablets can run any application. The very large number of applications is the main reason why people buy Apple's iDevices and I think that without it now iOS would not have been so powerful. Even though Google Play has been growing at an accelerated pace for several years now, I don't think it will overtake the App Store very soon, but when it does it won't matter much.
