Yes it's a Forum class I know but I don't quite know what you want to achieve?
Though I'll see what I can do generally from what I know.
Generally you'd want people to post Threads, Posts, be able to make User Accounts, and Forums by themselves.
I think you should start off with making an SQL class, then you should start with making an Email class to handle Emails, and then there is an IP class where you could handle all the Ips from the Users registering accounts, and generally if you wanted to ban someone, or ban their ip FROM the site you could do that with the use of WildHoney's ACL tutorial. :D
This is more SQL than anything so..
I suggest learning more SQL before starting to do this, there is another way, by Flat Files but meh..
This seems like the wrong forum for a Forum. :P Much more with Classes.. Isn't this the place for Advanced Programming.
One more thing, you should make a Template Engine. But I'd wait to make a Forum, till you are very familiar with PHP.
The Following User Says Thank You to Orc For This Useful Post: