Discoverability is the degree to which something, especially a piece of content or information, can be found in a search of a file, database, or other information system. Discoverability is a concern in library and information science, many aspects of digital media, software and web development, and in marketing, since products and services cannot be used if people cannot find it or do not understand what it can be used for. Metadata, or "information about information," such as a book's title, a product's description, or a website's keywords, affects how discoverable something is on a database or online. Adding metadata to a product that is available online can make it easier for end users to find the product. For example, if a song file is made available online, making the title, name of the band, genre, year of release, and other pertinent information available in connection with this song means the file can be retrieved more easily. Organizing information by putting it into alphabetical order or including it in a search engine is an example of how to improve discoverability. Discoverability is related to, but different from, accessibility and usability, other qualities that affect the usefulness of a piece of information. The concept of "discoverability" in an information science and online context is a loose borrowing from the concept of the similar name in the legal profession. In law, "discovery" is a pre-trial procedure in a lawsuit in which each party, through the law of civil procedure, can obtain evidence from the other party or parties by means of discovery devices such as a request for answers to interrogatories, request for production of documents, request for admissions and depositions. Discovery can be obtained from non-parties using subpoenas. When a discovery request is objected to, the requesting party may seek the assistance of the court by filing a motion to compel discovery. The usability of any piece of information directly relates to how discoverable it is, either in a "walled garden" database or on the open Internet.