First, I cannot believe that porn ALWAYS helps new technology. That is a very strong statement. I seriously doubt it influenced the light bulb or gasoline engine, just to name a couple things.
Fun fact: the porn industry backed HD-DVD standard, and it lost. Porn is not as powerful a force as one might believe.
The internet exploded with pornography because it was, for the end consumer, very very cheap. Have you guys ever actually priced paying for pornography offline? Maybe it was just the store I wandered into out of morbid curiosity, but some of that crap was $40+ per video. Compare that to internet, and it's easy to see why there was a flood of pornography, though I don't think that helped with adoption of the internet.