An audience hardly prevents me from using profanity, of course, but I like to consider my audience, as it were.
If I’m hanging out with old friends, I’ll swear as I find artistically appropriate provided this doesn’t bother them. Because it does bother some people, out of courtesy I avoid profanity around them unless it’s required to get their attention. (It usually isn’t, but I was once told that you’d never get anywhere with a phone company rep if you couldn’t say “hell,” and I’ve never had any reason to doubt it.) And I really avoid profanity around Bu because some words you need to know exactly what they mean before you start using them.
Of course, I can be startled into using profanity by the social equivalent of having one’s thumb hit with a hammer, but my point is that I make it a point to not make a habit of using profanity in front of a general audience in public, because the more people in the audience, the more likely that somebody in the audience will be bothered by my profanity, and I don’t like bothering people unless it’s my intent to bother.
Nothing terribly unusual about that.
What is apparently unusual is that I consider social networking sites public.