I agree that blaming Reddit is ridiculous. It seems like so many people have their panties in a wad about this, and I'm struggling to understand their expectations. Outliers aside, can one really consider the /r/findbostonbombers folks in the wrong? Do they require legal authority (per above definition) to do what they are doing? Are they violating any laws? Sure, they may include idiots espousing falsehoods in "witchhunt" fashion...but isn't the onus on readers to realize the difference between sources (social media vs. legitimate new reporting)?
This is crowdsourcing in action. It's changing the dynamics of news and dissemination of information. I foresee the development of some type of guidelines or protocol for future "Current events of significance," perhaps denoted similarly as on Wikipedia [1]. If not imposed by the content providers themselves (Reddit et. al.), then eventually by legislation. The objective would be to reasonably control (not restrict or censor!) the dissemination of information to minimize adverse consequences inherent with the flow of data.