I slightly disagree with your opinion on grassroots media. There are tons of quality blogs, websites, podcasts, and YouTube channels that wouldn't exist without the internet allowing for cheap production and access. Actually most of my information comes from these sources.
When the New York Times, the Guardian, HuffPo and the Atlantic all say X and a thousand blogs say Y, X is the story. We had alternative weeklies, zines and tape culture before the Internet, but the power to shape what people believed still belonged to a handful of organizations. The details have changed and which few organizations have that power has changed, but there's been no revolutionary change.
Right, and especially with the veneer of serendipity that you get from stumbling across (or upon ) a news article, it's easy to miss that there's a common set of beliefs behind most of it. They're not all that nefarious as hidden beliefs go, but you could still easily get the impression if all you read was these sites that you were doing everything a good democratic citizen should just by reading 8th grade reading level coverage that's designed not to scare off any advertisers. There's a huge unrealized potential for a more educated populace if we could collectively move past that.
I fall in between your two opinions. There are tons of quality sites out there, but they take a little bit of effort to find. That effort seems to be just enough to bias postings on reddit, hubski, facebook and probably every other large social media site heavily in favor of a handful of massive sources. Just check how many top-rated submissions are from The Atlantic, HuffPo, The Guardian, BBC or PBS. There have been a few interesting posts in /r/TheoryOfReddit recently with stats to back this up. It takes a concerted effort on the part of an online community - or a good blocking feature, thank you hubski! - to keep from being flooded by the same news that's already getting exposure everywhere else.
Very true re: your opinion on blogs/websites. The world of podcasts and YouTube channels are a different story. Almost all of the best content for both are provided by "grassroots" entities. Especially on YouTube. Everything from The Young Turks (politics) to VSauce (science) is being dominated by people who started with no institutional support and have remained successful as independent entities.