Abuse GitHub and use it as a chat with GitHub users who don't display an email, or just prefer GitHub.
Great for contacting publishers of Atmosphere packages that no longer have a repo, but the GitHub account still exists. If you are such a user it's probably because you've published a wrapper package, have worked with the original authors to publish official Meteor packaging, and are now asking you to hide your package from Atmosphere searches (while still keeping it installable by dependencies). You can do so with:
meteor admin set-unmigrated package:name
To remove mrt as a contributor:
meteor admin maintainers <your_username>:<your_package> --remove mrt
If you were originally the maintainer on the old package system, you can attach your Meteor Developer account at http://atmosphere.meteor.com/accounts, then ping @tmeasday to give you ownership of the old package.