[MrEyes]

It is difficult to say, but I would suggest that you don't discount current advertising revenue.

As an example you might be looking at a site with a million posts, 50k threads, 400+ concurrent users, blah blah blah. In other words extremely active - on the face of it it looks like a good site.

However it is also a site that will need a decent server to run, and this will cost. So if there is no advertising (or other) revenue creation on the site then you are looking at paying for that out of your own pocket.

Or maybe the site doesn't have any advertising / revenue creation on it and you are thinking of buying the "community" and then adding in advertising? You have to ask how the community will react to the introduction of advertising? I have seen active forums die in less than 6 months after the introduction of advertising.