That just happened. It's official; Microsoft is acquiring GitHub. I honestly don't know how to feel about that, and it's kind of scary. I don't think of Microsoft as a company who is excited about adopting free software. They have been major rivals, especially in the server/enterprise market, for a long time. Microsoft is now trying to gain footholds in the community, releasing their Windows Subsystem for Linux in June of 2016, and more recently delivering a keynote presentation at the 2018 Southern California Linux Expo. Now, they want to buy out the largest repository of FOSS on the Internet? I don't like where this is going.
Even before Microsoft acquired GitHub, I was wary of the company. They moved away from "free software" a long time ago, instead supporting "open source software", a rather weak term that doesn't actually mean anything about freedom. They scored an F in the GNU Ethical Repository Criteria Evaluation as of April 2016, and they have not budged despite being contacted by the Free Software Foundation about this and other issues like their new terms of service. Now that Microsoft is involved, I don't want anything to do with it. As far as I'm concerned, they've long since abandoned their roots in free software (if they ever had any).
Effective immediately, I am no longer going to be using GitHub. They have clearly demonstrated their lack of concern for freedom through their lack of response to the community about the aforementioned issues. I am afraid that the situation may be out of our control, and I therefore advise any responsible free software community to boycott and migrate away from GitHub as soon as possible.
EDIT 2018-06-06: To be clear, I had switched from GitHub to GitLab a long time ago due to GitLab's greater respect for freedom, refusing to use my GitHub profile and limiting my use of their services to the few group projects that required it. Now that Microsoft is taking over, I'm talking with all of my groups to switch as well to further my separation.