A system for full text indexing optimization that operates based on identification of idle and active content in a content source, and by prioritizing indexing of idle content over active content. Active and idle content items are automatically identified, and idle content items are given a higher priority for indexing, while active content items are given a lower priority. Active content items are generally those that are considered relatively more likely to be located by the user without using the full text indexing function, while idle content items are those content items that are relatively more likely to be located through use of the full text indexing function. The specific content item attributes that are used to determine whether a given content item is active or idle may depend on the type content source for which the full text index is being provided. Additionally, the determination of which content items are active and which are idle may be based on predetermined, static criteria, and/or dynamically determined use patterns determined by monitoring operations performed on content items by a user.