I had growing doubts about the organization for a long time. It seemed to me that a large part of our faith was manmade and speculative and this bothered me greatly for a long time. The internet was instrumental in helping me solidify those doubts by exposing the history and errors of the past and in time would have gotten me to step out. But it was Raymond Franz's book which was the final nail in the figurative coffin. Once I read that book, everything I suspected fell into place; heck, there was things going on that I wouldn't have suspected in the first place such as the depth of the societies duplicity .
The internet and JWD helps me to do continuing maintenance on myself when the doubts come. I also continue to read books about the witnesses and cults in general.