It's still popular in Holland and accessible via internet as well (http://nos.nl/teletekst).

I've been thinking about a sort of 'internet magazine' broadcast on old analog TV channels using a mechanism similar to how teletext works: a continuous stream of pages where more popular pages occur more frequently in the stream to reduce waiting time. The infrastructure looks very simple. Instead of RF, what about visible light? It's still possible for users to interact more closely by including slots with data directed for single users in the stream, with upstream via mobile data or wifi.