The game world of EVE Online is called New Eden, a vast setting of over 5000 mapped solar systems and more than 2000 uncharted systems that can be found through wormhole exploration. The game has an interactive 3D map of the galaxy where solar systems can be color-coded according to the filters a player chooses. Pair that with a feature of the client that keeps track of each solar system you've visited, and you've got a colorful visual representation of how much of New Eden you've seen.
EVE player Kirith Kodachi created a meme of sorts where players take a star map screenshot showing where they've been in New Eden and share it with others on their sites (or Kodachi's own, Inner Sanctum of the Ninveah blog). You can check out where it started with Kirith Kodachi and follow the 'links to this post' at the bottom to see where it leads.