At this time, and in a culture where online access is now an imperative, Wikipedia has become the definitive encyclopedia. In terms of its support for chemistry it is rich in many encyclopedic pages including named reactions, chemical and drug pages, articles about chemists, and many other forms of chemistry related information. Wikipedia is hosted on Mediawiki, an open source platform that can be utilized by anybody as the basis of their own hosted content collection. Mediawiki has been used as a collaborative environment by a number of chemists to create As a general contribution to the community Mediawiki has been used to create a number of resources that have become very popular with the chemistry community. These include VIPEr to support inorganic chemistry, ChemWiki as an online textbook and other educational resources and a Chemical Information Wikibook. Mediawiki has also been used by the author to host open source collections of data including scientists, scientific databases and mobile apps for science: the ScientistsDB, SciDBs and SciMobileApps wikis. This presentation will provide an overview of some of the chemistry resources that presently exist and celebrate the major contributions that Wikipedia and Mediawiki have made to the collaborative dissemination of chemistry.