There are different types of active involvement options in Tor, such as downloading the Tor browser application and running it as a client, running a relay, or using a bridge. Most users prefer the first option and connect to the Tor network for their own use. According to the statistics today, there are around 2 million direct connections each day. The top 5 countries of use and their percentages are United States (15.64 %), Germany (8.90 %), France (6.27 %), Russia (6.14 %), and Brazil (4.68 %).
The second option is running a relay. Tor is not only technical but also a social network of volunteers who share network bandwidth with others. Running a regular relay, not an exit node, is a straightforward process. Debian/Ubuntu distributions of Linux have the necessary packages in Tor repositories. A Vidalia Relay Bundle does the same thing in Windows environments.
The third option is running a bridge. Tor clients need to get a list of active relays in the network to start creating the circuit. Once established, the network flow will start from the first relay. But what if that relay, or even all relays in the circuit, are inaccessible to the user? This would make it impossible to join the network. This is a common technique for ISPs in Tor blocking countries.
Bridge relays, known as bridges, in short, come into play at this stage. Bridges are unlisted, hidden relays that users can leverage as a first step to accessing Tor. Even if an ISP is blocking all the relays, users can still connect to Tor with the help of bridges. There are different ways of learning a bridge’s IP address, such as sending an email to firstname.lastname@example.org with the line ‘get bridges’ in the email body. An automatic reply will send 3 IP addresses to the sender instantly.39