I'm assuming bad things in most others? This universe is a bit different though. It doesn't seem to have much of a lasting effect on the world, just adding in "fictional" people to the roster of people that already live here. And some of them have powers that normal people don't. I think it's been going on for about four years now. I've been here off and on for about three.
Rose can probably explain it a lot better than me though. I'm not really someone that's overly versed in alternate dimensions and whatnot.