The friends list is a system in Dino Storm that can hold up to 25 players by default, or can be increased by purchasing a slot from FredEx. To add a friend, go to their profile and select "Add as Friend". The players name tag will turn green and will appear in the "Friends" interface if you add them to your friends list.
If a player is your friend you can track them by opening the "Friends" interface, clicking on your friend's face, and selecting, "Watch Player." This will show you where they are and how much health they have.