From an epic-length state of the Guild Wars 2 address from game director Colin Johnson, commenting on plans for the upcoming months:
…we’ll make improvements to culling. We recently ran small tests on Live to help us move towards eliminating as much culling from [World vs World multiplayer] as possible. The results have been promising, and we have a number of additional culling features in development. If all goes well, our hope is 2013 is the year culling ceases to exist, or is as minimal as possible in the WvW experience.
Culling is Guild Wars’ technical trick to make it such an attractive world. The idea is that when you have a whole mess of characters on screen, the game makes a judgment call about which characters to not show you (i.e. cull) so that you can maintain an acceptable framerate. In theory, this seems like a great idea. But in practice, this often means characters right in front of you are invisible, doing things most games don’t let invisible characters do. Such as attacking you. The problem is particularly pronounced when it’s most important to see everyone, namely during crowded battles when you should be carefully picking out targets. That’s hard to do when you can’t see the target.
Johnson’s post also notes Guild Wars 2 has sold three million copies. Three million! If you were to lay those copies out end to end, you would be at a complete and utter loss when it came to the copies that were downloaded. It was so much simpler to lay things end to end before digital distribution.
(Screenshot from this post at Guild Wars 2 Junkies.)