Can MyBB forums be laced with any sort of viruses? Say if I was to visit a sketchy MyBB-powered forum could I catch any thing?
No not technically.
If the user has uploaded shady crap, then yeah, there's every possibility. But not if its a bog standard MyBB install
It's this forum:
<snip>
Violates the showcasing rules but not like anyone here would even be interested in joining the crappy site. Do you think I'm safe?
Please don't link to sites with illegal or unethical content.
It completely depends on the administrator's intentions. As the owner and maintainer of the site they could do whatever they like. That's not just limited to MyBB forums, but any website on the internet.