you can missuse is as such. You can also (miss)use a Forum as a blog. (or a blog as as CMS).Wiki isn't a cms too?
The main purpose of a forum is that many people dscuss with each other
The main purpose of a wiki is that many people are able to write the same articles
The main purpose of a CMS is that view people can write different articles[/b
using phpBB as CMS is like using a toothbrush to sweep your courtyard. It's kind of working but not not such a good idea.