Calling Minecraft "voxel" is sure to introduce confusion. The representation of the map is simply a regular 3D grid of block IDs. When we use the exact same type of regular grid to represent 2D maps, we do
not call the grid cells "pixels", so I don't think it's very informative to call these "voxels".
Minecraft is also not a voxel renderer. Voxel renderers typically work by casting rays against the grid. Minecraft draws the blocks with rasterized triangles, using a hardware-accelerated 3D API (LWJGL), just like almost every other 3D game.
In other words, there is practically no interesting overlap between what NovaLogic was doing, and what Minecraft does.