The lovely and fantastic Internet Archive has exactly this, for US News TV (Eg. C-SPAN IIRC) and they say they have clips from 594,000 shows since 2009 availabl

The lovely and fantastic Internet Archive has exactly this, for US News TV (Eg. C-SPAN IIRC) and they say they have clips from 594,000 shows since 2009 available. From what I've read and heard, they basically eat the subtitle/close caption track that's baked into the video/audio stream. Feel free to check it out at https://archive.org/details/tv https://archive.org/details/tv and search around for some fun terms/words. If you really like it and if you like the Internet Archive, feel free to donate a one-time sum or set up a subscription at http://archive.org/donate/ http://archive.org/donate/ - they're a US-based 501(c)(3) non-profit organisation - so donations are tax deductable if you're US based.