Introduction
What are ACLs?
ACLs versus Traditional Permissions
ACLs though powerful add additional complexity to the system and do have some limitations. You will notice throughout the Bonsai Framework we add ACLs only when absolutely necessary.
References
Good introduction from the Ubuntu docs - https://help.ubuntu.com/community/FilePermissionsACLs
Slightly Skeptical view on ACLs - http://www.softpanorama.org/Articles/slightly_skeptical_view_on_unix_acl.shtml