My own pet hypothesis is that after blogs became a popular and mainstream phenomenon sometime around the early-to-mid-oughts, there was a huge outburst of enthusiasm by a lot of smart contrarians with interesting ideas, who though this would be a new medium capable of breaking the monopoly on significant and respectable public discourse held by the mainstream media and academia. This enthusiasm was naive and misguided for a number of reasons that now seem obvious in retrospect, and faced with reality it petered out fairly quickly. But while it lasted, it resulted in some very interesting output.