This topic describes Freebase as a free, open database of the world's information and as an information community, providing some technical background and suggestions on how to participate.
Freebase is an Open, Shared Database of the World's Information
Freebase is an open, shared database that contains structured information on millions of topics in hundreds of categories. This information is compiled from open datasets like Wikipedia, MusicBrainz, the Securities and Exchange Commission, and the CIA World Fact Book, as well as contributions from our user community. Freebase differs from other databases because it allows one topic to belong to multiple information categories, also known as domains. In a typical database about movies, for example, you would find one topic for Arnold Schwarzenegger as a film actor. If you wanted to include information about Arnold as a bodybuilder, like which years he was Mr. Olympus, you would either have to create a new topic, or an entirely new database, that could store the bodybuilder-related information. Because Freebase uses a different underlying structure (technically speaking, Freebase is a graph database) Arnold Schwarzenegger can be "typed" as an actor, politician, citizen of Austria, and bodybuilder, all within the same topic. Since Freebase topics function as information hubs, rather than as the information containers found in other databases, users can easily contribute diverse facts about a topic, even if they belong to different domains of information, without having to create a new database or topic.
Freebase is an Information Community
Freebase is built on cutting-edge database technology, but it's also built on a community of users who want to contribute and use structured information. Like Wikipedia, Freebase is open to all user contributions, from filling in a simple fact (like Arnold Schwarzenegger's birthplace) to creating new types that can serve as the basis for collecting more information on a topic (for example, Arnold's topic includes a user-created type, Impersonated Celebrity, that tells us Arnold was impersonated by Rich Little and Phil Hartman). Where Freebase differs from Wikipedia is that the structured nature of Freebase information ensures that there is always consistency for all topics of a particular type. For example, any topic typed as Film Actor will always have fields for Film Performances information, whether that specific topic is about Arnold Schwarzenegger or Gong Li.
The structured information in Freebase not only ensures a level of consistency from topic to topic, it also makes it possible for users to mine information from Freebase and re-use it as the basis of other applications. It's easy enough to use conventional search to find a Freebase topic, but the Metaweb Query Language(MQL) and the Query Editor tool let users pose complex questions like "What other American movie actors have also held political office?" Freebase also offers a number of Application Programming Interface (API) services for developers to create applications that use Freebase data. In the future we'll be adding more features that make it easy for all users to create their own information collections and share them with others.
Getting Started with Freebase
Anybody can search Freebase, but by registering you'll be able to contribute to the world's largest open structured database, create your own types to add to topics, and even become the master or mistress of your own information domains.
After you're registered, check out our Freebase Community page, where you'll find email discussion lists for data modelers, application developers, and special interest groups focused on music, food, motorcycles, and other information domains.
