1. One or more computer-readable storage media that store executable instructions that, when executed by a computer, cause the computer to perform acts comprising: receiving a video; using optical character recognition to identify an item of text that appears in a first segment of said video; applying a tag to said first segment based on said text; determining which one or more second segments in said video meet one or more similarity criteria with respect to said first segment; propagating said tag to said one or more second segments based on said second segments meeting said similarity criteria with respect to said first segment; and storing said video with said tag in a tangible medium.