I disagree with that but I'm NOT surprised in the least at the contraction and the reason is obvious imo.
BIG companies, like Google with +1 groups, are trying to be the everything of the internet. What they see as improvements (more visitors, more revenue) come at the cost of less visitors for existing sites and fewer sales by sites with less presence online.
The telling part of that article is "if you taker facebook out of the equation" and it already didn't include google sending visitors to Google properties(shopping!) or Bing to Bing properties etc.
We're losing small sites daily. Even if they are still online they are quickly buried in search rankings the moment they get popular and pop up on radar.
Eventually there will be no need for solo publishers, bigger outfits can and will cover your subject soon enough. I blame the anonymous easy access to ad revenue, you don't need to forge and maintain relationships to get paid anymore.