ReadAbility

You could argue this is the original tool for this job, and it's good at it. Working on any browser with bookmarks, ReadAbility is installed by dragging a bookmarklet to your shortcut bar. Then, when you're reading an article on a particularly busy site, you can simply click your bookmark to remove all formating. Nice!

There are even plugins for Chrome and Firefox, both of which allow you to customize the look and feel of pages you make readable.

Safari Browser

readability web application

If you've got Safari, you've got a simple way to reduce online clutter while reading. One of the useful features of Safari 5 is the "Reader." Based on ReadAbility, this plugin provides a simple way to just see the article you're reading. Click the "Reader" button in your taskbar and you're good to go. It even parses multi-page articles to one page, meaning you don't have to keep clicking "next page" to keep reading. Brilliant!

iReader

readability web application

Want something like Safari Reader in Chrome of Firefox? You're in luck! You can download iReader, an extension for decluttered reading in Chrome and Firefox. Like Safari's Reader, iReader parses multi-page articles for you. Unlike Safari's Reader, you don't have to use Safari. Nice.

Instapaper

readability web application
instapaper

More than a way to remove distractions for an article, Instapaper is a way to manage your bookmarks and reading list. Heck, it even offers you an iPhone app, a Kindle subscription and an ePub download, meaning you can read your saved articles on practically any device. If you've got such a device, you'll love Instapaper. Even if you don't, though, it's a pretty great tool for saving articles you want to read later - and reading them distraction-free.

NotForest

readable online

This one's pretty. Like Readability, installation is as simple as dragging a bookmarklet to your toolbar. Unlike Readability, you can quickly and easily change the text and background color: just select from the options at the top-right. It doesn't seem to support pictures at all, but it's still a great option to check out if you're not quite happy with any of the above plugins and tools. Check out NotForest right now.

Know of another? Please, share it below. As usual, also feel free to ask anything about how to use these plugins, because I like to help.