RTFA, and you'll discover the following:
- The 40% figure is based solely on the author's job board (which this article was meant to promote).
- He makes some vague claims that he's "been tracking a few of our closest competitors for a couple years," and that data "trends along" with theirs, but he offers no concrete numbers, and the the plot he provides actually shows no such thing.
- The author provides no real, provable explanation as to why this is (supposedly) happening.
He may still be accidentally right about the jobs market, but this article really says only one thing: that 40% fewer people are using Authentic Jobs. And I'm more willing to conclude from that that they're getting their asses kicked by Indeed and LinkedIn.