Can I add a column to the comments listing in admin?

Can I add a column to the comments listing in admin? For example, I am using the app to leave testimonials and have a checkbox so that the admin can show chosen testimonials on the homepage. It would be good to add a column for this checkbox on the list of live comments so that the admin can easily see which are currently shown on the homepage.

Also, what is the 'score' column all about?