[hcazz]

To me at least, the different types are easy to understand.

White-board - the color of the board is white, it is used for dry erase markers.

Black-board - the color of the board is black, it is used with chalk.

Chalk-board - the color of the board doesn't matter, it likely uses chalk to write with and is therefore a "blackboard" as well.

[Izkata]

Chalkboards are green, it just happens that the name also encompasses blackboards.