I have heard about this term ..this is something related to giving theme to your site structure but i havent used this technique as if yet...
Link siloing is a great way to tell search engines which pages of your website are closely related when you cover a number of different content niches, or when your navigation list all pages code-wise but only makes related category pages available to users from an interface point of view.
"Siloing is an advanced search engine optimization technique that when used correctly can help solve the problems that occur when sites accidently dilute their available PageRank with erratic and unfocused linking." You know it by other terms "Page rank sculpting"