Turf provides an extensive API that makes it easy to create third party projects.
Here are some links to current third party projects based on Turf

• Turfa.nu
  Extensive statistics from the game, from game wide to user specific.
• Turfportalen.se
  Create your own toplists independent of the in-game lists.
• Turf.lundkvist.com
  Sums up zones in regions and areas
• Turf.urbangeeks.org
  A map tool that provides extra information on zones
• Turf - Area of influence
  A different and very nice way of looking at the turf map