User rights/responsibilities

User Rights - I'm of a mind that the same rights people enjoy in life should be given in the digital world.  I guess the actual usage and expression of rights depends on what country you live in, but you could use the U.S. Bill of Rights as a measuring stick.  People should be able to express themselves freely, not infringe on the rights of others, etc.  

User responsibilities - Is there any reason why, once visiting a site or before posting a comment, a page of user responsibilities that must be agreed to before being allowed to post, can't pop up?  These responsibilities may change from country to country or from whichever online entity one is doing business with (a school, a private business, a public business), but everyone should know the responsibilities that need to take place.