Some embodiments provide a system that provides a UI for delivering content to a content reviewer. The UI includes (i) a first UI tool for receiving a user query and for searching a set of content items based on the user query, (ii) a second UI tool for retrieving a set of tags associated with each particular content item, and (iii) a third UI tool for generating a list of content items based on the retrieved tags. In some embodiments, each tag in the set of tags is associated with a computed metric. The tags are sorted based on this metric in some embodiments. The metric of some embodiments is based at least partly on a user type. User types include content provider, content retriever, and content evaluator. In some embodiments, the UI also includes a UI tool for receiving content or presenting the list of content items through a communications network. In various embodiments, the communications network may be a network of networks (e.g., the Internet), a private network, a public network, a wireless cellular network, etc.