If you use domtool to set up your domain, there is a way to allow system:anyuser only to list the contents of public_html without breaking your website(s). By default ACLs R and L are given. Change that in this way:
fs setacl ~/public_html system:anyuser l
Now, add all permissions for the USERNAME.daemon principal:
fs setacl ~/public_html <USERNAME>.daemon read
Be aware that this only works if you use your own domain -- if you use http://hcoop.net/~USERNAME/ to serve your files, then you must be sure that system:anyuser can read ~/public_html and its subdirectories (have permission "rl" and not just "l").