I remember a few years back when a company called eToys.com set up shop and began selling toys online.
There was already a website called eToy.com which was a group of artists in Switzerland and Austria doing some very interesting things with web technology. I was one of their early eToy.TANK subscribers.
eToys tried to force eToy to give up their web address claiming that it violated their commercial trademark and so began the "ToyWars." The eToy.com domain was shut down while the matter was in dispute. The eToy community went ballistic.
The eToy group began a massive email campaign, contacting their entire member list and asking people to buy "Culture Stocks" to fund their legal battle. Simultaniously, they waged a "viral" email campaign (encouraging people to send the email to everyone on their address lists) against eToys to the point where not enough people would buy their products to keep them in business.
EToys went broke fighting the force of the internet and conceded defeat. eToy got their domain back.
You can still visit eToy.com. They have art and cultural activities going on all over the world, funded by loyal stockholders.
Blogs can have the same effect, and are more efficient since you don't have to send the whole message, just a link to it.
Dan Rather resigned last week in part because he released a document on his CBS 60 Minutes show that turned out to be a forgery. It was a blog, "Power Line" that was apparently the first to uncover the fake:
http://www.powerlineblog.com/archives/007760.php
A company of any size, and a person of any importance would be smart to check the internet for any positive or negative buzz being generated about them.
Blogs (and email) are the force, and if the force isn't with you, you're toast.
With power like that, bloggers have a reponsibility to get the facts straight.