In Australia, if you have a social networking account such as Facebook or Twitter, or if you use Internet message boards or forums, you are bound by this country's laws when you post material or express yourself. This issue has become readily apparent with the recent '#twitdef' case, which saw an Australian journalist threatened with a defamation lawsuit over her posts on Twitter.
A page on the Australian Media and Communications Authority's Web site provides examples of some online behaviour that could see you in trouble. It also has advice on what to do to avoid any accidental defamation or libel, useful links to government agencies, and information about staying safe online.
For example, the Web site states that if someone declines your friend request on Facebook and you continue to harass them, your behaviour could be considered stalking under Australian law. Similarly, posting videos of illegal activities online means they can be used as evidence against you if you are charged with a crime.