It's difficult to tell what forum software that is, as there are no links and nothing in the source. It is possible that it is custom software for that specific site. It wouldn't surprise me given that they have a whole custom OS as well.
i guess so. i've been using the OS for a longtime and i seem to find it easy to use the forum as well. but i guess its not available. i've sent a message to thomas the owner but i guess he won't give it away.
A lot of forum software does allow guest posting; I highly recommend NOT using that though. Even with captcha's you'll start getting bot-spam like you just can't believe. That said, it should be an option in most.
Edit: Although I seem unable to locate -where- that setting is in MyBB...