How was this data collected?
The connections shown here were collected from in-game system.log files acquired from compromised routers.

How are the player connections identified?
Individual players can be identified from their behavior in the log files. It is fairly simple to determine a player's first-hop origin servers, but nearly impossible after bounces.

How can I prevent myself from being tracked?
Through the typical in-game methods, delete your log entry when you connect to a router. (But please don't, because it would be impossible to make this map.) :)