Based on the traffic from the site there are probably several millions of users If the forums close is there anyway to capture all those users? There are already a few that popped up but their population is small.
I think one way is to create a specific forum about films and movies to cater to this specific niche audience?
It's going to be next to impossible to catch all of those stranded users. Might be better idea to pick a niche say comedy and focus on that as it's easier to target these people.
If a website that already has the right kind of audience (movie fans) is getting out of this business, it's a good signal to not enter it on our own as well.
They probably got sick of dealing with the live stream spammers We get a daily flood of them here - they must have been inundated with them at IMDB