Google Compatibility Test Suite (CTS) User Manual - Manual (Page 3)

1. Why build compatible Android devices?
Users want a customizable device.
A mobile phone is a highly personal, always-on, always-present gateway to the
Internet. We haven't met a user yet who didn't want to customize it by extending its
functionality. That's why Android was designed as a robust platform for running
after-market applications.
Developers outnumber us all.
No device manufacturer can hope to write all the software that a person could
conceivably need. We need third-party developers to write the apps users want, so the
Android Open Source Project aims to make it as easy and open as possible for
developers to build apps.
Everyone needs a common ecosystem.
Every line of code developers write to work around a particular phone's bug is a line of
code that didn't add a new feature. The more compatible phones there are, the more
apps there will be. By building a fully compatible Android device, you benefit from the
huge pool of apps written for Android, while increasing the incentive for developers to
build more of those apps.
Android compatibility is free and easy.
See the Android Compatibility program introduction for more information:
http://source.android.com/compatibility/index.html
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