1. A method of identifying data to store in a metabase, the method comprising: displaying with one or more computer processors a user interface that allows a user to input a user-defined tag expression, wherein the user-defined tag expression comprises information associated with data interactions the user desires to track; tagging entries in an index of data interactions that record modifications to data objects, wherein tagged entries are associated with data interactions that meet the user-defined tag expression, wherein the tagging associates a tag identifier with the tagged entries; accessing a first data object associated with a first tagged entry, to obtain first metadata about the first data object that is not stored in the index of data interactions, wherein the first data object is stored separately from the index of data interactions; obtaining second metadata from the index of data operations, wherein the second metadata comprises at least the tag identifier associated with the first tagged entry; storing in a metabase the first metadata in association with the second metadata such that the metabase associates the tag identifier with the first metadata obtained from the first data object, wherein the metabase is stored separately from the file system containing the first data object; and in response to a user request for information about data interactions associated with the user-defined tag expression, accessing the metabase to determine data interactions that meet the user-defined tag expression without accessing the plurality of data objects in the file system.