Keeping your email address private
help.github.com
help.github.com
Rather than a fake email, you could set it to "your_username@users.noreply.github.com" -- That's the email address used when you make edits from the web.
I would recommend everyone to use multiple emails. One personal for friends, one for open-source (perhaps commercial) activities and third provided by your employer. Hiding your email is not really long term solution.