"How do we know it's Snowden?" The same way you attribute credibility to any story you read (on the Internet or anywhere else), the reliability of its source.

"How do we know it's Snowden?" The same way you attribute credibility to any story you read (on the Internet or anywhere else), the reliability of its source. The Guardian says it's Snowden, confidently enough to make it public. It boils down to how much you trust them as a reliable news source. If they weren't sure, I believe they'd evaluate the possible backlash to their credibility and not run the story at all.