For instance, in order to block Facebook you only need to block all connections to the Facebook site. The methodology used to block sites is to block the link between your computer and the servers that host that site. Each node in the network required to connect you to the site is able see the destination site (say Facebook) along with the location of the computer who requested the information (you). The website (say Facebook) receives the request, and then sends information back through the network to your computer. Whenever we plug our computer into the internet and try to access a site, we connect to a local router which then sends a request for information through the network to the server hosting the website. In reality, these links are cables that crisscross the entire world, and even go under the oceans to connect continents together. Essentially, the internet can be thought of as a giant network of servers (nodes) connected to each other with links. In order to understand how these organizations censor we first have to understand the underlying structure of the internet. Essentially, they are restricting access to specific sites, such as facebook, because they have no control over the content. Many organizations (such as high schools) and countries (such as China) censor parts of the internet in the interest of controlling information. Unfortunately, not everyone in the world has access to an unfiltered internet like we do in the US. These days you can find just about anything with a simple google search.

The internet is an incredibly powerful tool designed to transfer information.

Tor web browser for facebook