In RC modeling parlance, an "analog" servo uses an older technology analog servo amplifier (amplifier = controller in this terminology). A "digital" servo uses a servo amplifier with a microprocessor in it. Digital servos tend to have more torque and higher response times for the same motor and mechanical assembly.

(Note that there's no fundamental reason you couldn't build a super-hot analog controller; it was just never done, and would have been much harder to stuff inside an RC servo case, so the world had to wait for itty bitty microprocessors).

In RC modeling parlance, an "analog" servo uses an older technology analog servo amplifier (amplifier = controller in this terminology). A "digital" servo uses a servo amplifier with a microprocessor in it. Digital servos tend to have more torque and shorter response times for the same motor and mechanical assembly.

(Note that there's no fundamental reason you couldn't build a super-hot analog controller; it was just never done, and would have been much harder to stuff inside an RC servo case, so the world had to wait for itty bitty microprocessors).