I ran the following command, when logged into my shared Linux host to see what user Apache was running as:
ps aux | egrep '(apache|httpd)'
And it was the same user that I use on the server.
ie.
myuser@example.com [~/public_html]# ps aux | egrep '(apache|httpd)'
myuser 44904 0.0 0.0 61244 724 pts/0 S+ 15:43 0:00 egrep (apache|httpd)
Is that standard for shared hosts? On my development computer apache runs under the user www-data, and in documentation or tutorials on file permissions for certain CMS environments, I see reference to Apache working under the user www-data all the time.