14 DAY TRIAL // Roboto, the main font used on Android, Chrome OS, and Material Design is now open sourced and available via Google's Fonts directory, also via a GitHub repository, under the Apache 2.0 License.
When you say Microsoft, you automatically think of Arial. When you say Apple, you automatically think of Helvetica. Typography-wise, when you will say Google from now on, you'll be thinking about Roboto.
This font has been slowly creeping into every new Google product or interface redesign, and while already available since Android 4.0, it is now fully open sourced, free in all legal terms.
What this means is that you'll be able to add Roboto to any website via the company's Google Fonts service, or you can tweak its glyphs and build your own variants by forking the GitHub repository, complete with the entire font building procedures.
Roboto currently supports all Latin, Greek, and Cyrillic characters, and delivers more than 40,000 glyphs (characters) via a series of different font families (check them out on Google Fonts for a full preview).
The move is not surprising, especially after the company open sourced its entire Google Web Fonts directory at the start of March 2015 and is known for taking such actions in the past. Chances are pretty low if you expect the same thing from Apple, which has been slowly deploying the new San Francisco font with its newer products, in the anticipation of OS X 10.11 and iOS 9, the main products which will feature it as the default font.
To give credit where credit is due, Roboto has been created by Christian Robertson, and you can view the font's specimen presentation included with Google's Material Design visual language.