A young Katie and Kristie, and a shadowy figure who wants to pay them a visit, in “Paranormal Activity 3.” (Paramount Pictures)

“Paranormal Activity 3” — the third entry in the virally marketed horror franchise — arrives in theaters tonight with another narrative about the strange, demonic entity determined to torture a pair of sisters. It’s a prequel to “Paranormal Activity 2,” which was a prequel to the original “Paranormal Activity” released in 2009. And it’s another example of Hollywood’s attempt to appeal to the YouTube generation with a shocker that focuses on found footage, footage that suggests the sinister happenings we are watching are, in fact, real. Or real-ish.

But are audiences still willing to shriek along with that gimmick, as the infrared images of moviegoers flipping out in the commercials for “Paranormal Activity 3” suggest? Or is this sub-genre officially played out?

The notion of a documentary-style approach to horror is hardly new. Tobe Hooper’s “The Texas Chainsaw Massacre” pitched itself as a true story back in 1974. And the admittedly ridiculous “The Legend of Boggy Creek” — the “real” story of Bigfoot’s reign of terror in Arkansas — played with the notion of reality vs. fictional scares before that, in 1972.

But the modern concept of the found footage flick — one in which the audience is aware that they are watching home videos allegedly made by the victims or potential victims of the onscreen terror-mongers — was really born with 1999’s “The Blair Witch Project.” That film worked because directors Eduardo Sanchez and Daniel Myrick understood how to make effective use of the limited frames of their handheld cameras, and how to launch an ­­effective online viral marketing campaign long before most people even understood what that was. In the late 1990s, when the digital era was young, it was still possible to be fooled by the Internet. And “The Blair Witch Project” did that beautifully, genuinely convincing some people that its found footage was indeed real before they had seen even a single second of the actual film.

Since then, we have gotten savvier and found footage movies have become more common. “Cloverfield” scared some audiences and, at times, even made them a little nauseous due to its especially herky-jerky nature. No one believed that a film produced by J.J. Abrams actually contained legit found footage. But that didn’t stop it from earning more than $170 million worldwide at the box office.

More films, inevitably, followed suit, including “The Last Exorcism,” “Quarantine” and the more recent “Apollo 18,” which generated zero buzz when it was released in August, despite the Weinstein Company’s best efforts.

And then there’s “Paranormal Activity.” When the first one, which was directed by Oren Peli as a decidedly independent effort, came out, it felt like a small, genuinely underground fright fest, a testament to its roots as a DIY effort as well as a bang-up marketing job on the part of Paramount Pictures.

Now it’s two years later and the third movie — which may prompt some to wonder how much home video footage one extended family can possibly shoot — is not generating the same level of Internet chatter as the first one did. But critical response to the latest demon-in-the-suburbs film — directed by Henry Joost and Ariel Schulman, the duo behind last year’s Facebook cautionary tale “Catfish” — is trending mostly positive so far on Rotten Tomatoes.

Owen Gleiberman of Entertainment Weekly is a fan. “When you consider how the grimy, mangle-fest ‘Saw’ sequels have ruled the Halloween season in recent years, it's refreshing to think that the spook-show franchise that has now caught the popular imagination has replaced depravity and sadism with a 21st-century, video-reality version of old-school campfire shivers,” he writes.

Richard Corliss of Time is in the same camp. “The ‘PA’ experience is wonderfully instructive, communal fun in a movie house, where if you’re not jolted by what’s on screen then you will be by the sudden screams of your neighbors.”

But Alonso Duralde of The Wrap seems to have reached his found-footage limit: “Two movies later, even die-hard supporters are going to find all this stuff dully familiar.”

And Roger Ebert has, too. “Inexplicably, there are people who still haven't had enough of these movies,” he writes. “The first was a nifty novelty. Now the appeal has worn threadbare.”

Of course, ultimately it’s the audience who will determine whether “Paranormal Activity 3” and the found footage genre still have legs. Will you be among those standing in line this weekend eager to experience more long, tension-filled waits for something that — JOLT! — unexpectedly shows up on-camera? Or are you ready for the next horror trend, whatever that is? Post a comment, but please don’t write Bloody Mary three times in a row and hit submit. I’d prefer that this blog remain unhaunted.