Heres how Microsoft games the patent system to get Android licensing fees

In the last several weeks, a host of makers of Android devices have agreed to pay Microsoft fees for alleging using Microsoft patents when deploying Android on their devices.

Why is that happening? It appears that Microsoft may have found a way to legally game the patent system.

Source:
http://blogs.computerworld.com/18591/heres_how_microsoft_games_the_patent_system_to_get_android_licensing_fees