It's really interesting how much of the history of online services actually pre-dates people having computers in their homes. They used purpose-built terminals and TVs.
It makes sense that there was so much use made of televisions, since these were large displays people already had in their homes. So you'd have a terminal, perhaps built into the television, that could display graphics that were better than the computers of the time for a lot less money. The computer would be on the other end of the phone line, radio signal, cable, whatever.