How to count bones?

Considering that the documentation recommends less than 30 bones for mobile devices, I would like to know in which way the bones must be count: 1 joint = 1 bone or like the bones into the 3d software (connection between two bones).
Thanks in advance.

Yes, one joint = one bone. That info may be dated. If you examine the models in the unity examples, characters have up to 70. Keep a limit on the # of bones per vertex and thy frame rates shall be plentiful.