October 20, 2013: Files can be shared (by Google account users) as "view only" outside domains with those who do not have Google accounts. From within a GAFE account, your users can share Docs, Slides, and Drawings to email addresses not linked to an existing Google account. The files are "view only." If the receiving person wishes to be able to edit the file, he/she must sign in with a Google Account in order to edit or comment.
Note: Google Apps administrators can prevent this by disabling sharing outside the domain to people who are not using a Google account (Admin Console setting).