Where or what plans do you prefer your forum hosted? VPS? Dedicated? Shared? For me, if it's small or just your friends or clubs, use Shared and don't waste plenty of money, unless your rich. If big like a community or fan forum, would prefer VPS or Dedicated.
Shared hosting is usually fine for forums, but as they get bigger and bigger they may need to look into their own servers, depending on the hosts restrictions, etc. FP is a good example of this as they are massive, but still run on shared hosting
FP on shared!? well that's nice, I think depends on admins too, but my host is free and unlimited disk space I think FP's share host is unlimited too.
I have a nice VPS with cPanel licensed and I use it to host all my sites and projects. I could sell hosting if I wanted but I'd rather not.
It really depends on how big and active your forum is but at the same time some huge forums do fine on a shared server. I wouldn't switch to VPS unless I really needed like if AdminBB started acting up and being slow and what not.
HawkHost's recommendations are if you are hitting 20 concurrent connections, then shared hosting is not for you, and it's time to move on to your own server: https://support.hawkhost.com/index.php?_m=knowledgebase&_a=viewarticle&kbarticleid=150
same here, I wish I could use cloudlinux I must nag the developers of the WHMCS Abuse Monitor to add such a feature in, lol