Img source: railscarma.com
It is no doubt that there are certain pages that you do not need to have them viewed by all the visitors of your application. You can also have users of different roles that may not be allowed to access certain parts of your applications. There is a really good Ruby gem called cancan that excels at this. It makes the authorization of your app resources pretty straight-forward, so you do not have to duplicate permission checking code across controllers and views.
