Next summer, “Dark Shadows” marks its 50th anniversary.

The supernatural soap (1966-1971 on ABC) didn’t have a long run as far as daytime serials go – “General Hospital” recently celebrated its 52nd year on the air – but it made a mark like no other.

With its suspenseful tales of remorseful bloodsuckers, handsome ghosts and malicious witches, “Dark Shadows” captured the imaginations of housewives, college students and kids, who would race home from school to watch the show spin out its increasingly crazy stories.

It spawned two big screen films starring original cast members, a Gold Key comic book that ran until 1975 (four years after the show’s cancellation), a series of paperbacks, two board games, two trading card sets, puzzles, bobbleheads, a short-lived NBC revival in 1990. Cast members still unite for original audio dramas in the “Dark Shadows” universe produced by Big Finish Productions.

We won’t talk about the Johnny Depp/Tim Burton fiasco, other than to note that its creative failure did not drive a stake in the heart of the phenomenon.

Fans today still talk about the stories, debating who Vicki Winters’ parents really were or how Angelique died in 1840 when she appeared in the 1960s stories. Picking out the bloopers is practically a sport – the show was taped as much as possible like a live theater show and because it was so expensive to edit tape then, everything that went wrong pretty much aired. Cast members swatted away flies, tried to manage malfunctioning props and jockeyed for a glance at the teleprompter.

But one thing doesn’t get spoken about, much, if ever.

“Dark Shadows” was terrifying.

If you’re an adult coming to the show now, that idea must seem laughable.

But if you were a child of the ’60s fortunate to be around when the show first aired, “Dark Shadows” fed your nightmares.

In late 1968, “Dark Shadows” introduced Quentin Collins (David Selby), a ghost in the Collins’ mansion of the West Wing. His abrupt appearances in front of children or the nervous housekeeper were chilling. How did the show do it?

Sure, easy to see now, in retrospect. The actor took his mark while the camera was on someone else, and then stepped off while the camera was trained on the screaming victim – making it seem as if the malevolent, mutton-chopped ancestor had indeed disappeared.

Later that year, Barnabas (Jonathan Frid) journeyed into the past and reverted to his cursed state as a vampire. Whenever he bit one of his victims, you could practically hear a chorus of screams across the neighborhood. Of course, kids would deny it to each other. Other kids made a game of daring another not to flinch first.

Kids then didn’t have much exposure to horror. The Gothic soap aired at a time when there were only five or six viewing choices (three commercial broadcast networks, plus PBS, plus two local channels). There were no Internet spoilers or chat rooms – and no Internet – and no way to binge the show. You had to experience it live, right at the time it was aired weekdays, no reruns, unless you wanted to hear about in the school recess, and that was the worst way, because then you’d be so upset at what you’d missed – and maybe a little confused, as “Dark Shadows” moved fast.

But if you were a child of the 1960s – as I was – catching the show as it aired, it was astonishing, riveting, maddeningly addictive television. It was a gift created by people who relished chaos and lunacy. They changed TV and the world, and we are all better for it.

In this era of binge TV, “Dark Shadows” has never seemed more relevant: All 1,225 episodes are available on DVD. You can purchase sets individually or the entire series here in a mini-coffin in which the cases lined up together depict a resting Barnabas Collins.

One of my favorite web sites in the entire universe is Dark Shadows Every Day. Writer Danny Horn reviews, recaps, dissects and trumpets one episode per entry. He’s obsessive, brilliant and hilarious, and if you’ve ever had any curiosity about the show, please check it out.

I am a child of “Dark Shadows,” and I can attest the magic, the pull and the power of the show has never diminished.