Presentations across cultures

How do presentations differ across cultures? I'm told Americans start a presentation with jokes, Japanese start a presentation with excuses.

Tyler Cowen was recently seeking advice on speaking to the Swiss.

So what are the fundamental principles of speaking to Indians, Italians, English, Germans, French, Africans, Aussies, Latin Americans, etc?

I'm also told that many people who work in multilateral agencies like the World Bank have perfected this art of cross-cultural presentations.

Your comments appreciated.