It's not a matter of it's a culture fit or not, it's a matter of showing that you care about the job.

We wear whatever the hell we want to at the office, but if I conduct an interview and the interviewee comes wearing jeans and a T-Shirt with holes, I problem will end the interview short and thank him for his time. If he doesn't care about this job enough to even make an attempt at dressing up then why waste our time.

Same with swearing. If you can't show to us that you care about this job enough to use professional language for an hour then I probably won't consider you past the first round. It's not whether we care about swearing, it's about proving to us you really want this job.

I think swearing sounds unprofessional, no matter how informal the company environment is.

Good tips.

I agree. I was once interviewed by a company who asked me to look at a snippet of code and tell them what’s wrong with it. It was supposed to to be testing for a handle leak; open db connection without a corresponding close. But right smack dab in the middle was a SQL injection bug. As soon as they handed me the paper I let out a whispered “FUCK”. Everyone laughed, and the rest of the interview went well, up to the compensation package ;-)