Every time you get on the web, where you point your browser can be recorded. Whether you're at work, on a public wireless network at a coffee bar, or even at home, your web travels are an open book if the network is being monitored, either at the Internet router or from within your wireless network. And often, web sites can tell where you're visiting from based on your computer's internet address.
That may not usually be a problem. After all, if you're at work and using the company's network, they have a legal right to know where you're surfing on their dime, right? But there are certainly legitimate reasons to not want to have where you go on the web monitored. Internet service providers often sell the internet browsing records of their customers—without their names attached, but identified as belonging to a user. That information might be enough for a marketer or another organization that purchases it to identify you. And often, your internet address can be used to narrow your location down to a specific neighborhood—or even a specific street.
There are also times when you're traveling when you may not want where you go on the Internet monitored. And sometimes, you may find sites are blocked by your company or ISP, or not available because of the network you're connected to, for questionable or capricious reasons (such as when Fox blocked access to Hulu and its web sites from customers of a cable company it was in a contract dispute with).
It's for all these reasons (and more) that Tor was created. Tor is software you can install on your computer that will uses a private network of proxies to send Internet requests as encrypted data , hopping from computer to computer on the Internet on a random path to the destination and back. Each person using Tor becomes a "node" on the Tor private network, acting as a relay for others, effectively hiding where each person's web browser is pointing.
There's another big reason to use Tor—to help people in countries with censored Internet access get to the web. Tor lets bloggers, journalists, political activists and others in countries where access to some sites is blocked circumvent national firewalls, and allows them to anonymously send out information about events in their country that might otherwise result in their arrest and persecution. When you run Tor and set it up as a relay, censored users can use your Internet connection to avoid oppression.
I've tested out Tor as part of a software bundle for Mac OS X, but Tor is also available for Windows, Linux and even the Android phone OS. The package for Mac, Windows and Linux includes Vidalia, a program that lets you start and stop Tor and configure how Tor handles things like relaying, allows you to reset the path your browser traffic follows, and get to other configuration settings and information. There's also Torbutton, an add-in for the Firefox borowse that lets you enable or disable Tor, depending on what you're trying to do with the browser.
There's a reason you may want to turn Tor off sometimes. Some sites may not work properly with Tor running because of the way it routes you. For example, when I tried to visit one company's website, I was forwarded to their German language site because the relay I arrived from was in Germany.
If you're traveling, using someone else's PC or are somewhere where you can't install software on a computer and want to use Tor to protect your browsing, there's another way to use Tor. The Tor Browser Bundle is a Tor-powered web browser that can be run from a USB drive, You can also get a version of the bundle that includes a Tor-protected instant messaging client.
There's only one problem with Tor—because of the way it works, people monitoring networks may not be able to see where you're going, but they may be able to figure out that you're using Tor. So the best way to protect your privacy is to make sure all your friends and co-workers know about Tor, too.