In my opinion worlds greatest business mind hunt is Viral Marketing.
View one very popular viral video from source: http://www.worldsgreatestbusinessmind.com/20090329-Pankaj-Pandey-create.html.
You can see how this video is spreading world wide. for this time viral marketing is the biggest and successful media for marketing.
Following are some information about viral marketing.
Definition: Marketing phenomenon that facilitates and encourages people to pass along a marketing message.
Viral marketing depends on a high pass-along rate from person to person. If a large percentage of recipients forward something to a large number of friends, the overall growth snowballs very quickly. If the pass-along numbers get too low, the overall growth quickly fizzles.
At the height of B2C it seemed as if every startup had a viral component to its strategy, or at least claimed to have one. However, relatively few marketing viruses achieve success on a scale similar to Hotmail, widely cited as the first example of viral marketing.
content source: http://www.marketingterms.com/dictionary/viral_marketing/ you can find more article there.