Safari's Reader feature is a cool little app that displays a web page as a newspaper article --- without all the distracting sidebars, comments, and ads. Sometimes it works and sometimes it doesn't, and I'm wondering how "it knows when to show up." On my personal website, one of the pages has this option. You can click the Reader button in the URL bar and it is displayed beautifully like a page in an iBook. However, none of my other web pages (on the same site) do this. I thought it had something to do with the <article> tag, but I removed that and it still works. Anyone know how this app works?

Also, does anyone know of any Chrome extensions that are just like this? Google Reader is not the same thing.

PS: From the cited Apple website:

Safari Reader

As you browse the web, Safari detects if you are on a web page with an article. Click the Reader button that appears in the Smart Address Field and an elegant view of the article appears — without any distracting content.

Not much help, is it?