Do you think that a forum that focuses on "link exchanges" succeed? Of course the forum would have seo, website reviews, business, web development help, etc. sections. But if the focus in is on exchanging links, do you think there is enough of a market for that?
It really depends on your marketing techniques. You need a reason for webmasters to come back on your website, and if you have something unique, you got it.
I think webmaster community is already occupied with a lot of forums....and they are minority who uses internet. I would rather focus on forum for general interest people
It would really depend on how you market. It could be great for people looking for real estate related, web related, health related, etc link exchanges. You could also post free articles, information all about linking, and maybe links to free link checking tools to keep visitors coming back.