Who Sets Your Price?

I received one of those chain emails the other day. This one stated that the oil prices are controlled by a few people, and if everyone banded together and stopped purchasing gas (or petrol for your overseas types) from only a few select companies, it would pressure them all to reduce the price. From what I hear, this has been going around for a while, but the prices do not seem to be affected (other than going up!).

This begs the question, can consumers work together to push prices lower on a commodity? I think back to these global trade sites that I've been visiting. If they sent a message to all of their members requesting them to stop buying from a certain company (forget the negative press they would get), I wonder what kind of effect they would have? Could the same thing work for diamonds for example? Diamonds we all know are a controlled price commodity.

When the consumer word of mouth power of the Internet meets the marketing power of the corporation, who will win out in the end? This has caught my interest so I think I'll do some more research and let you know what I find.