How do I add Disqus comments to my theme?

To enable comments:

1. Sign up for an account with Disqus, at http://disqus.com, by clicking "Add Disqus to Your Site"
2. Make a note of the "Shortname" you choose when signing up
3. Enter your Disqus shortname in theme options
4. Turn on "Enable Disqus Comments"
5. Click "Save"