Every piece of the manifest can be described in detail by associating metadata with it. SCORM metadata is recorded in a well-defined format known as “learning object metadata”, or “LOM”. LOM contains many predefined fields for describing learning content. SCORM also permits the extension of LOM to allow organizations to specify additional metadata. Metadata can be applied to virtually any section of the manifest, for instance it can be applied to the course as a whole, to individual items, or even to individual resources and files to enhance their reusability. Within the manifest file, metadata can either be specified inline within the XML (recommended for small amounts of metadata, especially at the course level), or it can be specified by linking to an external metadata file (recommended for large amounts of detailed metadata). Metadata is typically optional, however SCORM 1.2 does place some restrictions on the minimal subset of data that must be specified if any data is specified. The appropriate amount of SCORM metadata to use will vary widely depending on the intended use of the content, its anticipated longevity, and likelihood that the content will be reused.