I don't know by what magic this happened, but not only is Thumbtack back online, but everything appears to be intact.
As my young dev friend Brian would say: WOOT!
Since I didn't get any warm and fuzzies from anyone I tried to contact about this, I have no idea about the what/why/how long... as for me and mine, I'm scraping all this into OneNote if it's still alive when I can get it and OneNote both up at the same time -- i.e. not from Work :(
I'll use it but I won't be an idiot and not have a backup
Thank you Mrs. Thumbtack wherever you are! -- and my apologies to Jimmy Durante.