Android is more important than any other OS first because, it is OPEN-SOURCE, which means anyone can download the source files of any version of android and use them for their ends. @Senduci don't think android is very cheap... can you find a jailbroken iphone with a modified OS? show me a hundred phones like that and ill accept android is cheap.
It is also built off Linux OS, which became famous when Un*x was all the rage during the last few decades. so android naturally got more followers.
Also, anyone can develop an app and publish it on play store. today, apps are all the rage in many countries.
Fast and efficient data storage.
Platform for innovative app development without licensing fees for mobile manufacturers or developers.
Designed to support diverse hardware platforms.
Cost of customizing Android apps is comparatively cheap.
Simple and powerful SDK (Software Development Kit).
Popular language Java used for developing Android apps.
Excellent enterprise platform with superior level of access and control.
Your apps can share messages or exchange data --- all in a secure environment.
No differentiation between native apps and third party apps.