From Journalism to Churnalism : Stephen E. Arnold @ Beyond Search

Perhaps you've seen this before

"The browser extension will be available for Chrome, Internet Explorer and Firefox (full approval pending). The process works by enabling Churnalism to extract article text from a whitelist of common news sites. When it finds a match, it lets you know when the text you are reading might have been copied from another source. The capabilities of this extension are driven by open-source text analysis technology."

From Journalism to Churnalism : Stephen E. Arnold @ Beyond Search