In many occasions you might want a SWF to be able to retrieve data from another domain, by loading variables from a text file for example, or you might want to send data from a Flash email form to a PHP script that is sitting on another domain.With Flash player 6 a security sandbox implemented a restriction : a movie sitting on one domain would be prevented from loading data from another domain. In Flash Player 6, sub domains of the same parent domain could access each other's data this is not the case anymore starting with Flash player 7, domains must be identical for data to be read.