Yep. Pretty plain explanation if you ask me!
He was going to shut down a year (or two?) ago due to lack of funds and lack of time to manage the boards.
Several of us here made various offers, from simply volunteering to help manage the boards to actually buying the site from him.
All were turned down, but at least he decided to continue the board himself.
Sadly, it looks like this time it might well be final.
Sad to lose a valuable resource.