First, you should know that at the time that this page was created the phrase "Controlled Opposition" did not exist in either the dictionary or WikiPedia.org.
Controlled Opposition is when a deliberate attempt is made to either create an opposing effort to any existing power base, or, to obtain control of any opposition to one's own efforts. Some protest movements are actually being led by government or corporate agents. Nearly all governments in history have employed this technique to trick, co-opt, and subdue their adversaries.
Wiki Answers says: Controlled opposition involves a political organization used as a front in order to disseminate information useful to a ideologically opposed third party. IE a staunchly pro-capitalist intelligence community might deliberately set up a left-wing party in order to divide, confuse or discredit communism.
Vladimir Lenin: "The best way to control the opposition is to lead it ourselves."
Mossad motto: "By way of deception, thou shalt do war."