Although a few years old now, this Tom Scott video is still a fun reminder of how TV interactivity used to work before the internet:
There were a lot of embarrassing things on TV in the 1990s, and Andy Crane in a baseball cap was just one of them.
One point to note is that the fact you had to pay for interactivity (the cost of the postage both out and back) provided a crude but effective content filter. Interactivity didn’t mean a flood of insults and worse. Making things cheaper, and easier, can come with downsides too.