shutup.css is a custom user stylesheet that can be applied to your browser to hide comments on many popular web sites without user intervention.
To install:
- Download the auto-updating shutup.css file to your system.
(If you don't trust a remotely-imported CSS file, or want to make customizations, you can download the source directly instead.)
- In your browser's preferences, configure your browser to use shutup.css as a custom user stylesheet. In Safari for Mac OS X, it looks like this:

- Enjoy a less comment-y web.
- If you make changes, or download a new version of shutup.css, quit and restart your browser to make sure it takes effect.
A list of known-to-be-affected sites is contained within the stylesheet itself.
Warning:
The stylesheet blindly hides blocks with IDs like "comments", which could have unexpected side effects. (I'm told it hides the "discussion" section of Bugzilla installations, for example.) Disable shutup.css if you think you might be missing important page content.
Extras:
Safari 5 users can save some time by using the pre-packaged Safari Extension by Ricky Romero. It adds a toolbar button which allows you to toggle the stylesheet on and off on-the-fly:

Firefox users may wish to try the Stylish plug-in. Charles Stuart provided a Chrome extension.
Justin Ridgewell provided a bookmarklet to activate the stylesheet on-demand, rather than all the time. Drag it to your browser's bookmark bar:
Additions and changes are welcome → stevenf@panic.com
Thanks for your assistance: Cabel, Neven, Tim, and others!
