Regarding News.YC, I fear that it may eventually suffer the same fate as Slashdot, Digg, Reddit, etc. Trolling is a minor problem compared to self-promoting. The challenge is that there's no scarcity on the internet, so you have to create artificial scarcity. It may be that the best way to fix the problem (i.e. to create scarcity) is through fees. For example, a $1.00 (rising with demand) fee per submission would keep a lot of junk out of any discussion site. And any serious content producer or blogger wouldn't blink at the notion of a small fee. The assumption that everything should be free is what kills many of these sites.