Nearly everyone will have heard of Wikipedia. It began as a project and a software product. The concept was that an encyclopedia could be created online in a collaborative fashion. Wikipedia grew out of an online encyclopedia written by experts, but community content rapidly outpaced the expert contributions. In the first year only 20,000 entries were created. Wikipedia now boasts more than 3.6 million articles. Studies of accuracy have been done and place Wikipedia at an accuracy rate comparable to expert authored encyclopedias. It is the best case, worldwide, of community collaboration creating wide content, high quality content at a very low cost.
