"9! [years] I don't want to say that's the reason you're in the position you're in now...but it certainly can't have helped! I owe my mates there a lot.
"Alright...LET'S START LOOTING!" he added.
Williams also asked viewers to "remember the good times!"
"Hillary Barry [sic], John Campbo Live, Mike McRoberts in a flak vest carrying a tripod for no reason. Sam Hayes, Ali Ikram and David Farrier on nightline! C4! It was the best place I've ever worked."
Comedian Ben Hurley, who is a regular member on 7 Days, had a request for "whoever won Powerball the other day".
"Have you ever thought about owning a TV company?," he asked on Twitter, signing it "Sincerely, Ben".
Former Newshub sports reporter Sam Ackerman backed his former colleagues, writing:
"Anyone who buys Three off Mediaworks will find themselves with a workforce containing some of the most talented, hard working, genuinely good people you'd ever hope to meet.
"NZ has no idea how much it needs TV3 and Newshub, it would be devastating if they found out the hard way."
Other former employees from MediaWorks reminisced about the good times they had with the company.
"Also RIP Mediaworks, you gave me my start in comedy and didn't even call me a dirty traitor once when I left," writes Melanie Bracewell.
"7 Days and The Project were my first proper jobs (not inc kids parties and Weight Watchers) and I truly appreciate the work and experience they gave me."
It is understood staff were told just six minutes before the announcement was made public.
TV presenters had been called to one-on-meetings - though some of the network's biggest names are currently away. Newshub Live at 6 anchor Mike McRoberts is in Japan for the Rugby World Cup and Samantha Hayes is on maternity leave.
