Our website, like facebook, has a number of networks. Users are required to join at least one network. Each network will have its own forum, though these forums share the same structure. Can forum software support unlimited number of such forums on one website OOTB?
One step further, we are thinking of allowing user at his choice to post a topic visible, either within only the forum in his network, or across all forums on our site. Can that be done by marking individual topics for different visibility level, or setting up sub-forums at different visibility levels? Or we have to create two forums with one network-wide and the other site-wide?
Can a blog software be turned into digg style forum without serious customization? Or are there off-the-shelf software that provides such style? We don't care about voting up and down the post that much, but really like diggs flat forum structure with tagging.
For the type of functionality you're describing, you're looking at an expensive project. Just combining two forums is messy, let alone whole networks with the ability to pick and choose how much of the network you wish a post to appear on.
Not to mention, the HUGE problems you open yourself up to by doing that... Just imagine, a spammer comes along and spams one forum. You just made it WAY easier for that spammer to spam your ENTIRE network at once. You're actually making the spammers job easier. So, you may want to think about that idea a bit more before you even attempt to do it. Just a suggestion.