Tie into the user's mental model:  the visual front-end. This is the natural and intuitive way of how a nontechnical person percieves a website.  Website assets that can be identified and understood from viewing a page and its layout will probably benefit from front-end, in-line editing.  

(Caution: Many details of a website do not map well to a page or its layout, and these details are not served well with in-line editing.)