Tried it on Hacker News and IGN. Hacker News looks better without it. IGN becomes an empty page that shows one banner and nothing else. They do say that it's

Tried it on Hacker News and IGN. Hacker News looks better without it. IGN becomes an empty page that shows one banner and nothing else. They do say that it's meant to work on a page with only a single block of text, though, but based on the short video I was led to believe that it was supposed to get rid of the clutter and sidebars.