Source Organization: Wikimedia Foundation, Inc.
Description: A free, open content online encyclopedia created through the collaborative effort of a community of users. Check article References and Further Resources.
The free online encyclopedia that anyone can edit, with the mission of creating a world in which everyone can freely share in the sum of all knowledge. Over 56 million articles (6 millions in English; articles in 300 languages). An extensive worldwide group of volunteers manages, researches, writes, edits (120,000 editors), and reviews all submissions, based on rigorous standards.
In addition to simple search, Wikipedia has recent changes, featured articles, lists, and portals of various types organized by topic. Articles are continually updated and improved.
While Wikipedia may not be suitable for scholarly research, it’s an ideal place to start research–to get a sense of a topic by its components, vocabulary, history, relevant personages, controversial or notable issues, and related information. It’s also heavily used for quick reference.