Yes, rack pulls are a prime mass builder for the upper back/traps/delts and biceps. A key exercise for football players/wrestlers, etc. Power/hang cleans are right up there too.
Not only done with heavier weight and lower reps but can also be done in a higher rep scheme, with lighter weights. From 12 to 18+ reps. Have your breathing like a steam engine. Something like breathing squats and the excellent results gained by them. Can develop great stamina (endurance + strength).
As suggested by Chaos, DL's are supported by the upper body (keeping the body in a somewhat upright position during the lift) while the legs/hams/hip structure do the actual movement (you are pushing with the legs...like with squats). Holding or supporting a heavy weight can also have a benefit in gaining size and strength. Some will shrug the traps at the top position of the DL. SLDL's are more of a pulling motion, or should be, in the strictest terms.
Good Luck