As other commenters mentioned, you used Google Code, Sourceforge, and before that you'd email a patch to an email list, specific bug tracker for the project, or

As other commenters mentioned, you used Google Code, Sourceforge, and before that you'd email a patch to an email list, specific bug tracker for the project, or to the maintainer. Probably the biggest changes that Github added was the social aspect, and much improved UI compared to most previous tools. It made it much easier to search, browse code in the browser, and add requests to merge features or bug fixes.