FAQ

About Freebase

What is Freebase?

Freebase is an open, Creative Commons Attribution (aka CC-BY) licensed collection of structured data, and a Freebase platform for accessing and manipulating that data via the Freebase API.

How big is Freebase?

Freebase contains about 39 million topics (aka “entities”) at the time of writing; for the latest number you can visit the Explore page on freebase.com, which always has the latest numbers. There are hundreds of millions of assertions or facts about those entities.

Is Freebase a wiki?

No, though it shares some similarities with open wiki projects:
•Freebase is a free source of information
•Freebase is a collaborative project, and Freebase data may be edited by anyone
•Most of the data in Freebase is openly licensed under Creative Commons Attribution (aka CC-BY)

However:
•Freebase does not run on wiki software. Rather, it runs on a graph database that represents structured data.
•Most wikis arrange information primarily in the form of text-based articles. Freebase houses information in a structured, machine-readable database format.

What is a Topic?

A Topic in Freebase represents a single concept or real-world thing. Each topic has its own web page on freebase.com. A topic could also be called an entity, resource or element or thing, it is a fundamental unit in Freebase. All topics have the type /common/topic in addition to any other types they’ve been assigned.

Freebase contains many (15M+) graph nodes or objects which are not Topics. For example, ISBNs, paginations for books and Web page links.

What are Expected types?

An expected type aka ECT is a concept from Schema modeling. It refers to what Type or Topic is expected when someone fills in a property.

For example, the expected type of /people/person/place_of_birth is /location/location.

What is a Graph?

Freebase is a graph database. This means that instead of using tables and keys found in conventional database to define data structures, Freebase defines its data structure as a set of nodes and a set of links that establish relationships between the nodes. Because its data structure is non-hierarchical, Freebase can model much more complex relationships between individual elements than a conventional database, and is open for users to enter new objects and relationships into the underlying graph.

Is Freebase a Semantic Web project?

Yes, Freebase is part of the Semantic Web. We emit Linked Open Data (via RDF) for all our entities, and are involved in various SemWeb projects and communities.

What is Linked Open Data?

Linked Open Data, LOD, or Semantic web are terms that describe data that is meaningfully connected across different websites, and is accessible under an open License so that it can be combined and otherwise manipulated.

Terms and concepts include RDF, Ontology, Linked Open Data and Microdata.

What is an Ontology?

In Semantic Web terms, ontology refers to the categorisation and structure of data. In Freebase terms, we would call it Schema.

What is a Domain?

A domain is a collection of Types which share a namespace. It is typed as /type/domain. It can occur anywhere in the namespace.

About Freebase data

Why you use RDF?

There is few data models simpler than RDF, based on two concepts, the Node and the Triple. Because RDF schemas are expressed in RDF, you can use ordinary SPARQL questions to ask questions about schemas.

Where does the information in Freebase come from?

Initially, Freebase was seeded by pulling in information from a large number of high-quality open data sources, such as Wikipedia, MusicBrainz, and others. The Freebase community along with the internal Freebase team continue to drive the growth of the graph by focusing on bulk, algorithmic data imports, data extraction from free text, ongoing synchronization of data feeds, and rigorous quality management.

Why don’t you import…?

If you’re wondering why we don’t import a certain set of data or information, it’s possible we haven’t yet because:
•Maybe we didn’t know about it until you mentioned it.
•The licenses may be incompatible or the Terms of Service prevents us from doing so.
•We might already have planned to, but we just haven’t yet done so.

In cases of license incompatibility or unfriendly Terms of Service, we would need to seek permission from the owner of the data.

How do you ensure data quality?

Freebase relies on the same model of community collaboration and editing that Wikipedia and other open information projects have used. While some inaccurate information is inevitable, that same information can be corrected by anyone, and people make incremental improvements all the time. (For more information on our approach to intentional errors, see our contribution guidelines page on the Wiki.)

We have also developed a group of trusted Freebase experts to help keep an eye on things, and we believe that the efforts of a whole community keeps our information moving in the right direction. Finally, we have developed a large number of ongoing internal and community processes that help us maintain the integrity of Freebase data. We have feeds of new changes that community members can review, and scripts that we run to look for things that might indicate an error.

Do you use standard vocabulary?

Although Freebase uses some standard vocabulary, most schema information is expressed with non-standard vocabulary. This makes sense, since the Freebase schema supports a collaborative editing interface rather than RDFS inference.

Why is my data in Freebase? How do I remove it?

Information on personal data and removing personal data is in our Wiki. See: Personal data.

For developers

What are the limits on use of the API?

You may use the Freebase API for almost any use, including commercial uses, up to a limit of 100,000 API calls per day. See the Freebase Terms of Service and Usage Limits for more information. If you are interested in using the Freebase API beyond 100,000 API calls per day, please see the instructions in Usage Limits: Requesting additional quota.

What API libraries do you have?

See API Libraries page to see if there is a library for your language of choice.

Commercial and business matters

What are the rules for using data in Freebase?

The rules for using Freebase data depend on the type of content it is. Data is available for use under the Creative Commons Attribution Only (or CC-BY) license. This means you are free to use it on your site, as long as you credit the Freebase community appropriately. The Freebase attribution policy on the Wiki has all the details.

Many of the images in Freebase are also CC-BY, although some images are hosted under different license terms, such as the GFDL (which is similar to CC-BY), public domain, or Fair Use, and you can use the Freebase API to filter your results by license type. Finally, long descriptions that they have pulled in from Wikipedia are licensed under the GFDL.

Can I use Freebase data for my business?

Yes, you are allowed under the terms of Freebase’s Creative Commons Attribution (CC-BY) license, as long as you attribute Freebase as the source of your data. See the Freebase Terms of Service for more details.

API use is limited to 100,000 requests per day. If you need more, you have two options:
•Use the downloadable Data Dumps to work with Freebase data offline. This option is best for higher volume use.
•Increase your quota using the instructions at Requesting additional quota. This option is best for lower volume use above the initial 100,000 requests

Can I get a private installation of the Freebase platform?

Freebase does not offer an installable version of the platform for individual use. However, all the data is openly licensed under Creative Commons, and data dumps are available, so you can build your own application based on that data using a database backend or triple store of your choice.