What is the best when you set-up your new forum: is it to use a sub-domain or to register a new domain name just for your forum?
There are may free forum hosts out there where you get a forum hosted on a sub-domain. But then you are locked with the same forum host as long as you have your forum. You can never move your forum to another host because you can't move the sub-domain you use....
On the other hand if you host your own forum, then you must upgrade to new versions everytime they are released. No one will upgrade the forum for you (unless you pay them that is

)...
What do you think is the best? Hosting your own forum, or hosting your forum on a sub-domain with a free host?