In reply to whenry:
Yes, quite a few medics claim that. On the other hand, look at any high profile sports event, and half the competitors will be taped somewhere. Since the stuff is quite costly, it is safe to guess that the athletes agree that there is some benefit above placebo effect levels.
FWIW, I currently use kinesiotape for a persistent bursitis / patella tendonitis in the knee, works great and the mechanism is obvious: The tension in the tape simulates some tonus in the tendon without actually putting load on it, and pulling the knee cap slightly upwards prevents it pinching the underlying bursa when extending the knee.
For the rib injuries, the tonus effect is more important and useful for climbing or judo, but I agree it would not help coping with short compressions (skiing, mountain biking).
CB