Inspired by comment 23 on trac ticket #27111 this plugin allows you to globally toggle comment functionality across your WordPress installation including:
- Disable support for comments and trackbacks in post types
- Close comments on the front-end
- Hide existing comments
- Remove the admin comments page and comments menu
- Redirect any user trying to access the admin comments page
- Remove comments metaboxes from the admin dashboard
- Remove comments links from the admin bar