Deeplinking means you link to own of the specific pages on your site instead of the homepage Example Link to http://www.example.com/deeplink.html That would be a deeplink.
PR will filter down to the other pages in your site. The benefit of deeplinks allows you to build pr to your inner pages. This way you won't have to wait years for it to filter down.
Deep links means inner pages.Deep Directories means they accept inner pages of ur sites.It will help ur inner pages to get good SERP.