One way to help users locate just the right instructional streaming video to fulfill their needs is to organize them by subject. This section discusses open streaming collections by discipline. In keeping with the Choice taxonomy, the arrangement is alphabetical in three broad disciplinary clusters: humanities, science and technology, and social and behavioral sciences. Many of these discipline-specific sites are on larger platforms discussed above—for example, Ted Talks and Khan Academy—or are YouTube channels. This is indicated parenthetically in the titles of the sites. Readers are reminded that many sites could prove valuable in more than one discipline or cluster.