I'm guessing he's referring to this article:

https://www.quora.com/Why-hasnt-another-product-disrupted-an...

Which had quite a lot of visibility a few years ago.

The author argued in 2011 that craigslist would be an afterthought within 10 years. Its revenue has grown from 122m when he wrote that to in excess of 380m now. I think he's pretty clearly wrong.

I had no idea either. I use it almost every day.