This [Teletext/Cx, branded as CeeFax for consumers - http://en.wikipedia.org/wiki/Teletext%5D is (one of the many) the standard that my department (BBC R&D) helped invent - http://www.bbc.co.uk/rd/publications/rdreport_1975_12.shtml
I was a baby then but nowadays we still used the standard to test the next-gen DTV aerial signal 25 years on http://downloads.bbc.co.uk/rd/pubs/whp/whp-pdf-files/WHP160.pdf)
I was part of the team that moved the 'red button' services across to use same page numbers (with an extra digit prepended for content not available on analogue TV) - my former workmate Andrew wrote about this here http://www.bbc.co.uk/blogs/pressred/2009/05/assigningpagenumbers.shtml
Cx was always great for speedy updating, but the client (journalist) software was clunky. It did help the BBC learn the importance of writing concise summaries for textual viewing many years ago (which was very helpful when the Web came along)
It was always *digital* but TX-d on analogue circuits. I'll miss it, but the info there is still available, and guess what? Life moves on. > 98% of UK people have digital TV now and the switchover went well. Still free at point of reception, still advert-free.