I, too, have a more than 20 year history with YaBB. Somewhere in the last year, my last forum went dark. I don't even know why. One day it was working, the next day it was throwing up 500 errors.
I complained to my hosting company (I hadn't touched any of the code in more than a decade, so it wasn't a change on my side. It had to be something they had changed on their perl install or something like that.)
On the negative side, they had no belief that anything had changed in their servers. On the positive side, they went out and got a copy of the latest release YaBB software, installed it, and moved all of the messages of my forum over, which is FAR above and beyond the expected level of support on a cheap (something like $5 a month hosting plan) server place. Unfortunately, it had none of the mods that made my forum home to me, and many of them were not available on the newest release, which is why I wasn't using it.
But to a great extent, forums are not used nearly as much as they once were, and I have to admit my forum was dead long before it died. Had been a year since the last post, and in the year prior it probably got 6 or 7 posts for the whole year.
Many fond memories for many great people! Still wish Carsten a yearly birthday wish, but fond thoughts for those who have passed, or who've just fallen out of contact!