The Government primes the pump. Begun in 1980 at PBS flagship station WETA in Washington, DC, this was the one of first technical field trials of highly graphic broadcast TV "teletext" in the US (the graphics were embedded in the TV signal and displayed by a special set-top box).
As a government-sponsored project on a PBS channel, our 50-page teletext "magazine" was heavy on information and light on advertising. Still, I tried to give the pages a little flair with our "Uncle Sam" theme character.

We focused on:
We used the newly-defined Telidon platform, which allowed us to easily and efficiently create graphically sophisticated, highly animated pages. Though crude by today's standards, Telidon was really cutting edge for 1980. You had a total of 14 on-screen colors and its "byte lite" vector graphic language allowed fairly snazzy animated graphics.
One of the implementation challenges: Because of technology limitations (remember - these were the early days), every page had to be under 2000 bytes total.
Teletext embeds the digital page into the Vertical Blanking Interval of the broadcast television signal (The VBI is that black bar that appears when your TV picture "rolls"). You then extract and display a page by clicking a special button on your TV remote control. The vision thing was to have the decoder chip installed standard in all TV sets.
The technique is similar to the way in which closed captioning is handled.