Say that your forum was previously active. Then, members just kinda stopped showing up for x reason. You've tried and tried to save it. When do you know it is time to just give up on a forum that isn't getting anywhere? When do you know a forum has died?
I would prefer answers from a staff viewpoint, not a guest/member one. Although a member viewpoint could be valuable too.
I had a board that lasted for slightly over two years, although that's only technical .. Really, it was active for maybe only a year and a half. The last six-eight months were full of try-and-fail attempts by me and a few other veterans to get it going and active again, but everytime we tried, it just went completely inactive again. Eventually, I knew I had to call it quits -- no one was joining, and frankly, most/all of us were losing interest. And when everyone loses interest, you know it's gone, and maybe for good.
I wouldn't give up just yet. The ending to my board was pretty obvious; I mean, if no one wanted to keep it going, not even the admin, then there was no real point in leaving it open. However, if you've only tried once or twice to get it going again and you're still really into it, I wouldn't let your board go just yet.
Is it a staff issue? If you have inactive staff, that could be a reason why people are getting turned off. Inactive staff often leads to general disinterest, like it's some warning signal that says "STOP. THIS BOARD IS ABOUT TO DIE!"
I sort of agree with silent Cacophony. If your still really into the idea your board has, don't let it die. Try if anything to start it off fresh, maybe not entirely at the beginning if your site plot has already moved ahead and all. But if you have any inactive characters/staff send out some warning msg's if they dnt respond let 'em go. Its sad to do but sometimes ppl loose interest in things. Or Real Life gets in the way.
It's happened before and well... its sort of happening at the moment.. but i'm not a staff member on that site, i just know evry1 there. Still the Admin locked all the old threads and said "Lets move on to the New"
Have no idea if i helped or not... i feel like i rambled, i've got to get that under control. Hope i helped a bit.
I pretty much agree with SC and CS.
My recommendation is if you want to revive the board:
1 - Email each of the remaining players with an activity/interest check. Explain that you need to know if they want to stay with the game. And that to keep the game alive, everyone is going to have to help pitch in.
2 - Sit down with the ones who decide to stay and work out a plot revamp. Give them and their characters a stake in the story.
3 - Advertise like crazy. Like you would with a new board -- because, in a way, it is a new board. And don't just hit a few places and stop. Keep making the rounds. Haunt the 'looking for rp' areas here and at Looking For.
I won't lie to you, it'll be work. It'll be a lot of work. And it still might not happen. But it definitely won't if you don't.