21. At least one non-transitory computer-readable medium storing computer-readable instructions that, when executed by at least one of one or more computing devices, cause at least one of the one or more computing devices to: receive a content item that has been accessed by a user; determine at least one term associated with at least one of one or more search queries that resulted in the content item being located by a search engine and accessed by the user, the at least one term being useful in describing the content item; assign a tag to the content item, wherein the tag is associated with the at least one term; and place the tag in a categorization structure that includes at least one tag set.
24. The at least one non-transitory computer-readable medium of claim 21 , further comprising instructions for assigning at least one of a tag type, tag identification and a topic to the assigned tag.