Isn't that the reason we have trusted scientific peer review journals? I mean, why trust a paper that hasn't been vetted by a trusted source? The same is true in news media - I don't give any stock to news content that isn't published by a well-trusted source (and I do pay for subscriptions, e.g. AAAS, Financial Times, etc., for that very reason). I guess I don't understand the concern - the world has always been filled with junk information and we have tried and true systems in place already to deal with it.