Way back in the late 90s I had DirecTV and lived in a place that would fry anything with a phone jack if it wasn't unplugged during a thunderstorm. Lightening got the DTV box's phone circuitry (the rest of box worked fine) when we weren't home, and I didn't want to buy a new one. A buddy showed me how to hack the card with a reader/writer, and I was into the scene for a while (I continued to pay DTV their money each month; this was a hardware fix, not payment avoidance). It was fun working on something at such a low level. Far smarter folks than me were doing the actual hacks, but I had a grasp of what was going on. Very simplistically, the card acted like the cable TV filters on the side of your house, deciding what the box would and would not decode for your viewing pleasure.
By the time Black Sunday rolled around, I had purchased a new box and gone "legit". But I did read about it, and was impressed by a very cleverly put together and well-timed hack to make all of those cards go poof. What TFA doesn't mention, and maybe I'm remembering it wrong, was that it was the hacks themselves that did the cards in. DTV couldn't rely on their code to be there, since the hacks modified it. So DTV anticipated what the hacks would be, waited for them all to be in place, then pulled the trigger. IOW, the hackers indirectly did it to themselves.