This can be understood fairly simply from a materials standpoint.  In a typical racquet, the frame is made of layers of graphite, which are held together by a binding resin.  Over time the strains and flexing due to temperature fluctuations, impacts, and stringing begin to break down the resin binding the graphite in place.  This is why many professionals will replace racquets after about 6 months of play, some more and some less obviously.  Once the resin breaks down past a certain threshold, the racquet simply does not play the same as a fresh stick anymore.  It is unable to rebound as it should, resulting in a softer, spongy feel and less repulsion.  Now, by adding these Innegra fibers, which have a unique flex characteristics that acts to dampen vibration within the frame, Head has found out that the resin undergoes less stress and does not break down as quickly.  Overall, what we have, is a frame that is more comfortable, and longer lasting.

IG YouTek Speed MP (18x20):
100 sq. in.
11.1oz unstrung
27in
20mm beam
11pts head light
18x20 string pattern

Anyone can look at the YouTek IG Speed MP and know immediately that it is a serious control racquet.  From the thin 20mm beam to the dense 18x20 string pattern, this frame is built to allow strong players to maximize their potential through control.  Thanks to having a slightly larger 100 sq. in. head, it has a bit more pop and forgiveness than you would typically see in a players racquet.  A few of us here have gotten to take this frame out for a test drive and the response has been overwhelmingly positive.  We all felt that we definitely noticed the decrease in vibration compared to the previous model.  Only time will tell as far as frame durability goes, but on initial testing, this might be one of the better Head racquets we've tried.