Most websites and web hosts now have their own custom php.ini so as a hosted user, you would be interested in adding some of security to your website , a typical joomla security tip will look like this
open_basedir = /home/users/you/public_html:/tmp
disable_functions = show_source, system, shell_exec, passthru, exec, phpinfo, popen, proc_open
open_basedir = /home/users/you/public_html
Ofcourse , if you understand what you are doing, add to the disable functions list any commands you wish php to ignore and not parse, and when u doubt urself about a command, try on php.net/yourcommand and read more about it.