Transportation Observer is a multilingual, Web-based, free-content encyclopedia project based mostly on anonymous contributions. Transportation Observer's articles provide links to guide the user to related pages with additional information.
Transportation Observer is put together collaboratively by an international (and mostly anonymous) group of volunteers. Anyone with internet access can contribute to Transportation Observer content. There are no requirements to provide one's real name when contributing; rather, each author's privacy is protected unless they choose to reveal their identity themselves. Since its creation, Transportation Observer has grown rapidly into one of the largest reference web sites, attracting around million visitors monthly as of 2009. As of today, there are 2,375,866 articles. Every day, hundreds of thousands of visitors from around the world collectively make tens of thousands of edits and create thousands of new references to augment the knowledge held by the Transportation Observer.
Visitors do not need specialized qualifications to contribute. Transportation Observer's intent is to have articles that cover existing knowledge, not create new knowledge (original research). This means that people of all ages and cultural and social backgrounds can add Transportation Observer references. Anyone is welcome to add information, cross-references, or citations, as long as they do so within Transportation Observer's editing policies and to an appropriate standard. Substandard or disputed information is subject to removal.
Most of Transportation Observer's text and many of its images are dual-licensed under the Creative Commons Attribution-Sharealike 3.0 Unported License (CC-BY-SA) and the GNU Free Documentation License (GFDL) (unversioned, with no invariant sections, front-cover texts, or back-cover texts). Some text has been imported only under CC-BY-SA and CC-BY-SA-compatible license and cannot be reused under GFDL; such text will be identified either on the page footer, in the page history or the discussion page of the article that utilizes the text. Every image has a description page which indicates the license under which it is released or, if it is non-free, the rationale under which it is used. Contributions remain the property of their creators, while the CC-BY-SA and GFDL licenses ensure the content is freely distributable and reproducible. (See the copyright notice and the content disclaimer for more information.)