The aggregation of individual opinions, and the collectivisation of many small efforts, is a massive lever for -- and site of -- social change to which our culture is just now awakening, thanks to the evolving affordances of ICT. Wikipedia is the highest profile example at the moment. Its founder, Jimmy Wales, recently provided a very interesting take on this for the Long Now Foundation's Seminars about Long-term Thinking.
Now, in Chicago on 7 June there is a Summit about Prediction Markets -- another testing ground for the principles of collective wisdom (see this example run by the World Economic Forum). The Summit organisers have been distributing some interesting reading matter to delegates via a Prediction Markets google group.
Virtual reality doyen and film director Jaron Lanier's Edge.org article Digital Maoism: The Hazards of the New Online Collectivism, argues that the "hive mind" of the collective works exceedingly well for some things, and very poorly for others, but that the current fad for "wikitopian" thinking overlooks or denies the latter. Among the adverse consequences of what Lanier describes as "inappropriate uses of the collective" are compromises on the quality of information (both the content and how it's expressed), and a culture of avoiding individual responsibility. Whether or not you're inclined to agree, it's a very well written and thought-provoking article.
And either way, it's also helpful to develop a vocabulary for the huge amount of activity going on in this area. A possibly useful new term in this connection is "Crowdsourcing" -- Wired magazine's coined buzzword alluding to the latest examples of the ancient idea that many hands make light work. Could there be a more appropriate way to learn more than through this this Wikipedia article?