I really find that it's all dependent on the context. The use of profanity in a presentation (or the use of humorous images) can set the tone of the talk, and

I really find that it's all dependent on the context. The use of profanity in a presentation (or the use of humorous images) can set the tone of the talk, and in a larger context, sets the tone for the event. People have stated that profanity isn't appropriate in a "professional" context, and I think I agree with that. I don't use profanity around my clients, I wouldn't put it in a report, and if I wouldn't use it in a talk internally at my company. I work at a "professional" company. As an artifact of the industry I work in, however, I see a fair number of talks that aren't supposed to be part of a "professional" context. They're supposed to be part of a social context. In infosec, there's a continuum of "professionalism" in events which ranges from a bunch of folks in a bar giving talks while drinking to a conference like RSA. For what it's worth, I get way more out of events like the former (although certainly not because of people swearing). I think if you're giving a presentation at an event, you need to know what the context of the event is, and your presentation should match it.