Free Speech Dilemma-2

So this is dilemma that confronts everybody. For example, Hitler items sold on some U.S. websites are prohibited in some European countries, so is the denial of Holocaust in some European countries and not in others especially the U.S. Hate speech is a protected form of speech in European and other advanced countries but not in other countries and what constitutes a hate speech may not be such in other countries. Recently the issue of the Screening of the derogatory movie about the Prophet of Islam came to boil in Islamic countries. It was a free speech issue in the U.S. but for the people in the Islamic world, the word Free speech ends when you insult the Prophet of Islam (although curiously they tolerate other kinds of insults on other biblical Prophets). The explosion of new technology while it has eased human beings lives and make the world a little bit small has also spread the kind of speech some people or even countries don’t like. Now in some cases you can say whatever you want without fear of offending someone (with limits as has been shown by the courts). But this freewheeling technology has even the supporters of free speech uneasy too. My question is what is the limit of free speech, how do you define free speech, what universal body says that these things are off limits and cannot be considered free speech in any country. This is such a complex and vast discussion that it can never end because of different opinions and views of billions of people and thus this is also my dilemma since I may support free speech in some cases and not in others.