http://webdesign.tutsplus.com/articles/design-theory/using-metaphors-in-web-design/
http://www.thebestdesigns.com/design/designers/
http://sixrevisions.com/
http://sixrevisions.com/user-interface/5-reasons-why-metaphors-can-improve-the-user-experience/
http://tympanus.net/codrops/2011/11/30/inspiring-examples-of-symbol-and-metaphor-use-in-web-design/