Here's how it works. Click on an article or post on your favorite
website. Take a look at the Smart Address Field. If the word 'Reader' appears, you're good to go. Click on the word 'Reader' and you'll get a clean view of the page. If it is a multi-page article, they will all be there as you scroll down. Even better, you can print the page cleanly, or send it via e-mail. When you are done, navigate to the bottom of the displayed page and click the 'x' and you'll be back to the regular web. Check the screen shots for before and after renderings to see how it works.
I found reading this way to be a terrific experience. Reader simplifies the web, getting rid of a lot of the annoying sidebars and extraneous content. It won't work on a front page with lots of links to articles, but once you are in the article, it should re-render your page if you ask it to.
Note that not everyone is pleased with Reader, as it can impact advertising revenues for some sites (although it does load the complete page before it lets you go to Reader view, so it should not hinder pageview counts). It's a lot like the tension between television networks and the time-shifting/ad-skipping technologies that began with the VCR and continue today with DVRs. Ad-blocking and Reader views will probably be a flashpoint between content creators/advertising networks and the audiences they serve.