According to a report from The Wall Street Journal, Microsoft will be investing in Cyanogen, Inc., the Android ROM builder. The report says that Microsoft would be a "minority investor" in a $70 million round of financing that values Cyanogen in the "high hundreds of millions."
Cyanogen takes the Android source code and modifies it, adding more features and porting it to other devices. It has also started supplying Android builds directly to OEMs (like the OnePlus One), which ship the software on devices instead of stock Android. Last week during a talk in San Francisco, Cyanogen's CEO said the company's goal was to "take Android away from Google." It wants to replace the Google Play ecosystem with apps of its own, the same way that Amazon uses the Android Open Source Project for its Kindle Fire products but adds its own app and content stores.
Cyanogen says 50 million people are using its modified version of Android, which would put it at five percent of the one billion active users that Google touts. Nearly all of those Cyanogen users are still using Google Play, though. The real challenge for the company will be convincing its hardcore Android user base to dump Google Play and use the Cyanogen app store.