If someone forks your repository and commits some changes, what is the accepted way to proceed if you'd like to ask them whether it's alright to pull those changes in?
Can you issue a pull request on the forker's behalf and count on GitHub to alert them somehow? If not -- I notice GitHub doesn't support sending users messages; should you somehow contact the user outside of the site?
edit - By the way, both the question and answer are obviously different from the Q&A linked as "duplicate".