Guild Wars 2's world-vs.-world battles -- a little something like, say, enemies? That would be culling. In order to limit bandwidth and reduce client-side system requirements, ArenaNet instituted this process which limited how many characters would render on players' screens. However, a side-effect for those who entered WvW in large groups was that many enemies couldn't be seen even at close range. To end this invisible enemy phenomenon, culling is being culled from WvW.
In place of that system, ArenaNet is offering new options to customize how characters will be rendered on the battlefield. Players can choose exactly how many characters will be rendered in each of the following ways: as high resolution models, as low resolution models, and as just nameplates. These changes will be implemented in the March 26th patch.
[Thanks to Drew for the tip!]