Aside from shifts in morality and underlying cynicism that took place online from around 2007, once the "unwashed masses" because addicted to Facebook, I think

Aside from shifts in morality and underlying cynicism that took place online from around 2007, once the "unwashed masses" because addicted to Facebook, I think the biggest thing that killed good writing online was analytics. Once most people discovered their well thought-out blogpost got only 100 page views while a meme with a cat got 10 million, many just gave up. But what's missing in those numbers is, of those 100 page views, perhaps 10 were people you actually respect, have influence in your field, were actually using your Open Source project etc. By optimising metric like page views we lost sight of the genuine impact we might have had with good writing.