I think that using forum for support purposes is justified if you offer some plans that don't come with 24/7 support. In all other cases, I can't imagine a situation where someone would prefer spending time and searching for a solution on a forum (without any guarantee that the solution will be found) instead of just contacting support and getting any questions answered right away.
I don't have much experience with this though. If someone has positive experience with providing support through a forum to paid customers, it would be great to hear your story and your thoughts.
Originally Posted by Alex - Arvixe
Our forum is fairly active and works for us. We have a small support section for basic queries which we respond to (though the community can also which is great) though anything which would require a login would be taken to a ticket or other support channel.
I see that your forum is indeed very nice and active. How did you do this?
Why do you think your users prefer to go to forum instead of just contacting support through live chat/e-mail/phone? If they just hang out there, why not in social networks where you have your profiles and pages?