2. GitHub Repositories https://help.github.com/articles/github-terms-of-service/#2-github-repositories

GitHub repositories are intended to host Content. You may include static images, links, and promotional text in the README documents associated with your repositories, but they *must be related to the project you are hosting on GitHub* .

You may not advertise in other Users' repositories, such as by posting monetized or excessive bulk content in issues.
3. Spamming and Inappropriate Use of GitHub

Advertising Content, like all Content, must not violate the law or these Terms of Use, for example through excessive bulk activity such as spamming. We reserve the right to remove any advertisements that, in our sole discretion, violate any GitHub terms or policies.