Tomorrow, the full release of Minecraft will be available. In it, the sun will now be rising in the east and setting in the west. Some people might wonder “hasn’t it always been rising in the east?” No, not really.
The sun rises in the east on Earth. This does not mean that it rises in the east in every world, since it’s not the same sun, and it isn’t in the same position. (Also, Minecraft is a game, not an accurate emulation of the world. :P) The things that hint on what kind of cardinal directions Notch intended for the world are coordinates and maps. The z coordinate decreases as you move north and increases when you move south, while the x coordinate decreases as you move west and increases as you move east. Mapping directions to cardinal direction like this is common for 3D worlds. Maps are oriented with north up, which in incredibly common for modern maps.
In case you don’t believe what I said, Notch has actually stated that the sun rises in the north, so it’s pretty clear that the sun does not rise in the east in the old versions of Minecraft.
In the full release (as well as the 1.9 pre-releases), this is going to change. The sun is now going to rise in the east. Some people interpret this as “the sun is still rising in the east but the maps have been fixed so that north is up”, or similar statements which imply that the sun has always been rising in the east. This doesn’t make sense, unless you arbitrarily choose which direction is east (which is possible, since “east” is just a word that was designed to be used on Earth, not in other worlds). The places where the sun rises relative to the game world is changing, but everything else, like the movement of the clouds relative to the game world, the coordinates in the debug menu and the appearance of maps are identical to the way they were before.