Can someone explain the two to me?

Do they have anything to do w/ open and closed loop?

tia

STFT adjusts fuel ratio for whatever you're doing at the moment. If you just floored it, STFT adjusts the fuel to compensate for all the air suddenly coming into the motor.

LTFT is just that, long term. If the ECU notices that it's never had to put less than X amount of fuel in to compensate, then LTFT will be set to X. It takes a couple seconds for the ECU to compute LTFT, and several hours or days to build a new fuel map.

I think the STFT and LTFT are only used in closed loop mode.

Corbin wrote an AWESOME FAQ on our fuel systems:
http://www.2gnt.com/www/corbin/mfi.html