While I believe that words can do real and lasting harm (at least as real and lasting as, say, a broken arm, or a treatable cancer, and conceivably worse altho not typically), and pretending that they can't is a Foolish and Dangerous Political Position, I do not necessarily agree with the standard set of Bad Words. That is, I have no problem whatsoever with the monosyllabic words in Carlin's Seven Dirty Words (my primary issues with the polysyllabic words in his list revolves around not really wanting to explain them to small children -- the rest of them can be explained by pointing and/or an age-appropriate explanation of what sex is, all of which are reasonable things for small children to have some awareness of. I also feel that at least one of those words -- and not the one that starts with m -- draws its power from negative ideas about oral sex which I want nothing to do with). However, I definitely think that racist, sexist, words which are associated with negative ethnic stereotypes, words which draw their power from oppression in general, whether based on sexual orientation or other, _should not be uttered_. Bad. Don't do it around me.
So that's what I think about Bad Words.
Swearing usually involves bad words, and there's some reason to believe that the part of our brain which generates swears is different from the part of our brain that we usually use to speak (same place, other side, type of thing, IIRC). I have a kid who is not particularly verbal, but over the last few months, when he has been playing one of his iPad games and gotten particularly frustrated about something, he has started making a bunch of noises that sound suspiciously like someone swearing (there's a movement and gestural component, too). And embedded in those noises are a few identifiable syllables, including "poop".
Because of my husband's feelings and beliefs on swearing, I don't do a whole lot of it around the kids (or, sadly, at all). I think what I'm seeing with my kid is strong evidence that swearing has very little to do with modeled behavior.