blogs, the internet and censorship

I'm used to a free and open internet. And since I work in a library, I am also used to thinking in terms of choosing, but not censoring, for example, with book selection. But I have been hearing stories about censorship on the web, blocking sites, and fights being organized to keep the web free and open by organizations such as Free Press which is located in nearby Northampton.

One example I read about was a union in Canada whose web site was blocked by the local telecom. They were organizing to fight for better wages, etc. on their website. And there's the story about how a cell phone company blocked text messaging by a pro choice organization.

The thing is, I don't really understand how this works - how sites can be blocked and how traffic can be slowed to certain sites. People have tried to explain this to me using the analogy of a river that's flowing along, but can be blocked by a dam, slowed to a trickle by beavers, rerouted into a side stream, etc. Okay, I understand about rivers, but I don't know how this works with the internet and how this concept translates into the potential for blocking blogs, websites, and emails.

I would like to know more about how the internet works to get a better grasp on this. I think that as someone who works in a library and is dedicated to the free flow of information, I need to know how this can happen. I also want to know what I can do as a member of the library community to prevent this kind of web censorship. Is it even fair to call this web censorship?

I think web users make choices in what they access or don't, just as a librarian does in buying some books and not others. But for users to be limited by a company as to what they can access or not access is very different. I wonder if other people in the library science world are also concerned about this. When I went to an MLA conference two years ago, I didn't hear any mention of this concern.

So is there anything to this? Is it something people who work in libraries need to be aware of? These are some of the thoughts swirling around in my mind as I make my first ever blog entry.