suPHP/suexec type programs typically which let the script processes run as the user instead of the webserver user (nobody, apache, httpd, etc).
If you want to know for sure make a file called index.php and put this in it
<?php passthru("whoami"); ?>
If it shows your accounts user name, they're likely using suphp/suexec/fastcgi to execute the scripts and cgi's as the user... likely the perms 700/600 would work as well as any. If it shows nobody/apache/etc then they're not and you need less restrictive perms on the files for them to work 775/777 even.