Folksonomy
With so many people having the capability to contribute and create with the ease of modern technology and applications, Folksonomy is a system that is crucial to know. I absolutely love Instagr.am iPhone app which allows people to take/filter/ and share photos. I think the main reason Instagr.am is succeeding is that people can curate the content that is now coming in by the millions.
Definition:
A folksonomy is a system of classification derived from the practice and method of collaboratively creating and managing tags to annotate and categorize content;this practice is also known as collaborative tagging, social classification, social indexing, and social tagging.
In article by Daniel Pink: http://www.nytimes.com/2005/12/11/magazine/11ideas1-21.html