GitHub (and others) allow you to place a notebook on their servers that, once there, can be accessed directly using the nbviewer. The server has installed Python (and other language) coding needed to support your notebook. The nbviewer is a read-only use of your notebook, and is not interactive.

The nbviewer is available at https://github.com/jupyter/nbviewer. The site includes specific parameters which need to be added to the ipython notebook command, such as the command to start the viewer.