Domains are worth whatever a buyer is willing to pay, not what people in this thread or automatic tools on the internet believe/suggest.

I've had domains that I hand-registered in the last two years sell for 4-5 figures and other that according to experts/tools are very valuable, but that simply do not attract any buyer.

And I'm not even a regular domain investor (or domain squatter as people on YC seem to believe all domain investors = squatters).

Anyway, I think the blog poster has a pretty good idea of what his domains are worth, but he's just trying to raise attention and possibly start a bidding war on the 2-3 interesting ones. Some choose to do their auctions through auction houses, other uses more creative forms.