Vanilla 1 is an interesting bulletin board/forum system. I really like the philosophy and the way it’s built – it’s lightweight and simple, doesn’t try to add too many features to solve every single problem out of the box and it doesn’t have all the junk you find in a normal forum system such as private messaging and "My Assistant".
I downloaded and tried it out and it’s a real breath of fresh air. The team behind Vanilla have had the guts to do something fresh and they’ve done a real good job of it. The problem with lightweight boards is you’ve got to not only spend time installing it but then more time downloading extensions and installing them (Vanilla actively encourages you to install extensions; Firefox almost discourages you).
The semi-restrictive license (GPL) and the lack of themes and useful add-ins at the moment are a bit discouraging but the final version has only been released so this is definitely one to watch.
phpBB killer? Perhaps, but not yet.