Forum prototype - Constructive criticism requested.

[eluser]Dam1an[/eluser]
I'm still not sure if I prefer the use of set_id to instantiate the object, or just a constructor which takes the ID and creates the object.
With the Post, you would need to have multiple Post objects, so using the set_id, you would be overwritng the current one, instead, you need a set of them, same for forum (or do you have some eveil genius up your sleeve to get around that?)

As for the setters which don't change, just make the variable private, and you don't have to worry about it (you are using PHP5, right?)

Also, how comes you decided to go the pure OOP route instead of MVC? I know you initialy lowered your demands from MVC as you couldn;t find something to get ideas from, but looks like you're doing it from scratch anyway