It differs in that the height at which the BASE jumper takes his leap is much shorter. Between the time the jumper steps off the launch point to the time he throws the hand-held pilot chute is only three seconds. The shortest three seconds of the Base Jumpers life. Following the jump, skill is then needed to fly the chute and land without getting hurt.
Jumpers leap from still objects, as opposed to airplanes and other moving objects.
A typical BASE jump also has a landing area that is filled with boulders, rocks, or large trees on uneven terrain. Wind conditions are unpredictable from second to second. Therefore, a great amount of experience, education, knowledge and guts is necessary before taking the first leap. It is not about proving anything to anyone. It is just as adrenaline pumping as its relative, Skydiving.