Paul Krugman comments on how the growth in academic blogs in economics is a continuation of publication trends that long predate the World Wide Web: "Our blogs, ourselves".
First of all, policy-oriented research was never as centered on refereed journals as we liked to imagine. A lot of the discussion always took place via Federal Reserve and IMF working papers, and even reports from the research departments of investment banks. The rise and fall of Fed policy via targeting of aggregates, for example, was not a debate played out in the pages of the JPE and the QJE.
Second, even for more academic research, the journals ceased being a means of communication a long time ago – more than 20 years ago for sure. New research would be unveiled in seminars, circulated as NBER Working Papers, long before anything showed up in a journal. Whole literatures could flourish, mature, and grow decadent before the first article got properly published
It's a model worth examining, as Krugman notes the effect of blogs is to broaden the conversation to people who once were locked out of these conversations, but who are nevertheless affected by them.