Greg Linden posts about a paper by Sergey Brin and others that discusses the use of closed-captioning from television broadcasts as a tool to help find related material.
Several products are already around that allow you to search (via the closed-captioning) and view television content online.
+ ShadowTV (fee-based)
Utilizes the closed-captioning from most U.S. news networks and local stations in major markets, search in real time, view the video on your computer. Keyword alerts. Powerful search capabilities. You can register for a free demo.
+ NewsIQ (fee-based)
Monitor/search news broadcasts from more than 250 stations.
+ Virage (part of Autonomy) offers this type of technology. PBS provides several free (and useful) demos.
PBS NewsHour Video Search
Search segments of the program beginning in February, 2002.
Scientific American Frontiers Video Archive
"Every episode of the series, from 1990 to the present, is available for online viewing [and searching]."
Washington Week in Review Video Archive
The archive dates back to July 21, 2000.
American Field Guide
Keyword search (or browse),"the sights and sounds from a wide variety of environments throughout America. We've collected over 1400 video clips that enable you to experience America's wilderness firsthand..."
Nature Video Archives
Search by keyword and/or program title.
>From the site, This FREE professional development resource helps teachers quickly and easily find standards-based Mathline video clips and lesson plans on different mathematical topics and teaching techniques for grades K-12.
Julia Child: Lessons With the Master Chef
Keyword search (you can even limit by ingredient) and view online this PBS series.
"Search and replay congressional video within moments of the debate"
+ TV Eyes
They've been around for several years.
For more multimedia tools and talk, see Danny's post:
Search Meets TV.