I love TVTropes. They just take something (whatever it is, from the concept of McGuffin to the existence of love) or someone, and they dissect that concept or person and show you where the concept or the ideas of that person appears in books, TV series, films, and so on.
A golden example of what TVTropes presents is its site about the Bard, William Shakespeare.
http://tvtropes.org/pmwiki/pmwiki.ph...in.Shakespeare