For the US traveling for business is doesn't from "doing work". as far as they're concerned if you don't produce anything you're not "working". Meetings, attending training, attending or even presenting at a conference don't require a different visa. I have seen a university lecturer pulled aside and told he needs a special visa though.

AFAIK -- which is hardly at all -- the same is true for Europe and Canada. I've often been asked why I was entering a European country and have said I was on business without any further questions.

What countries don't require a visa for tourists but do for business troops like attending a conference or meetings?

It hadn't really occurred to me that there would be any but between Europe and the US that pretty much has covered out for me. I did go to Japan for a conference once -- should I have had a visa for that?