There are insightful comments on almost every site with UGC, even if said comments are a minority. We need a client-side aggregator of whitelisted/upvoted comments, to "follow" pseudonyms and merge comments and context from many sites. Alternately, there could be communities which curate/whitelist comments from multiple sites, then readers could "follow" a feed of curated comments. RSS was a step in this direction.
Any site which achieves economic infuence via discussion quality/quantity will eventually attract paid posters of various stripes, ranging from sophisticated misdirection to uncivil discourse. Whitelists can reduce the cost of filtering this noise, but sufficiently good propaganda can best be detected by readers who co-evolve with paid influencers: "... elite consultants have adopted grassroots advocacy tactics for paying clients. Rather than being dismissed as mere 'astroturf', these consultants' campaigns should be seen as having real effects on political participation and policymaking", http://www.amazon.com/dp/B00IO0E69E/
Manually curated Twitter lists, viewed on Flipboard
Private groups on Facebook
Niche/subscription blog comments
Amazon book reviews & comments (niche books)
HN comments/stories from whitelisted users
NY Times comments (quality varies by article topic)
Any site which achieves economic infuence via discussion quality/quantity will eventually attract paid posters of various stripes, ranging from sophisticated misdirection to uncivil discourse. Whitelists can reduce the cost of filtering this noise, but sufficiently good propaganda can best be detected by readers who co-evolve with paid influencers: "... elite consultants have adopted grassroots advocacy tactics for paying clients. Rather than being dismissed as mere 'astroturf', these consultants' campaigns should be seen as having real effects on political participation and policymaking", http://www.amazon.com/dp/B00IO0E69E/