OK, when someone posts 'bump' as a reply, what does that mean any way? Is it good, or bad?

it's a neutral reply...
it's like leaving an empty space.. mean nothing really

It's putting the good threads at the top to get shitty threads, like this one, off of the page. It, quite literally, bumps the thread posted in up. It's used when people post crappy threads, like you have, or just to get important shit to the top, like FAQ.