This is dangerous ground. While on the one hand when people pick up your content and re post this looks like you are an authority. On the other if it is a shared site and its goal is to inorganically spread the material Google will know. It works a lot like link farms. Google can spot that a mile away. If your content is good and people pick it up naturally than great. If the intent is to get back links for the exact content you are in dangerous panda waters. The other danger is to take your document and spin it. This is very black hat and almost guarantees being sand boxed. I do post some of my blog url's at Facebook and they get spread. Google sees this as natural. So in the end i would say to you to not do it. Write great content and let people pick it up naturally.
