Open Data is data that can be freely used and distributed by anyone to use, reuse, and redistribute. It requires data to be available, which means the data must be in the public domain or under license conditions that allow users to use the data without restriction.

Linked Data are datasets that make use of clear, unique identifiers that allow elements and relationships in different datasets to be identified as referring to the same thing. Linked data systems are built on a standard of World Wide Web (Web or Internet) technologies which enable linked data to become a global database. Linked Data enables links between datasets that are understandable to both humans and machines.

Open Data is not the same as Linked Data. Linked Data need not be Open Data, and Open Data need not be Linked Data.  Open Data is available to everyone without links to other data. At the same time, data can be linked without being freely available for reuse and distribution. Linked Data is enabled through a set of design principles for sharing machine-readable interlinked data on the Web. Linked Data enables the creation of a global network of data. The resulting network can automatically answer complex queries and analytics by searching the network of information and finding matches (known as Data Graph Traversal).

Linked Open Data is a blend of Linked Data and Open Data: it is both linked and uses open sources. The benefits of Linked Open Data: it breaks down information silos between various formats (often disparate sources and formats), facilitates the extension of data models, and allows for easy updates. The resulting data integration enables easier and more efficient searching through complex databases for information.

Main principles of the Linked Open Data:

• Uniform Resource Identifiers (URIs) are used to name and identify individual things. The URI is a single global identification system used to give unique names to anything (e.g., resources on a webpage; mail address; phone number; books; objects such as people and places; and concepts).
• All conceptual things have a name starting with HTTP (Hypertext Transfer Protocol)—an application (software) protocol in the Internet's model of distributed, collaborative, hypermedia information systems. HTTP is the foundation of data communication for the Web, where hypertext documents include hyperlinks to other resources that users can easily access.
• Looking up an HTTP name returns useful data about the thing in question in a standard format. Anything else that that same thing has a relationship with through its data also has a name beginning with HTTP.
• When publishing data on the Web, other things are referred to using their HTTP URI-based names.
• URIs provide a means of locating and retrieving information resources on a network (either on the Internet or private network, such as a computer.