Twenty years ago, “The Blair Witch Project” debuted at Sundance, creating an impact that’s still felt today.

The movie’s “found footage” format inspired multiple imitations and was a reminder to Hollywood of the huge audience potential for micro-budget storytelling. The movie’s biggest impact: It was a triumph of marketing, mixing old media with the newly booming Internet.

Directors Daniel Myrick and Eduardo Sanchez filmed for six days and nights in Maryland, on a budget pegged at $35,000. In a key move in 1998, before anyone had screened the film, they hired respected Los Angeles PR firm Clein + White. Then Haxan Films created a website to answer questions about the film’s “missing” students. And in December, Endeavor agreed to rep the producers.

The film screened in the Midnight section at Sundance on Jan. 25, 1999. By morning, Artisan Entertainment had acquired it for $1.1 million and added more post-production work, boosting the cost to a still modest $500,000.

Artisan began screening at colleges to generate word of mouth, and “leaked” trailers to the Aint It Cool News website, then to MTV News. The film’s own website received 160 million hits in the first three months, astonishing at that point.

Sci-Fi Channel aired a faux-documentary called “Curse of the Blair Witch,” with actors portraying historians and witches, the docu re-creating the “reality” vibe of the film.

There was also mainstream media buzz: covers of Time and Newsweek and stories on network news programs.

The movie opened on July 19 in 27 screens, averaging $56,002 per screen. It widened to 1,101 theaters on July 30, then doubled that number on Aug. 6. The film ended up earning $140 million in the U.S., with an additional $108 million overseas.

In an analysis of the summer’s box office, Variety’s Charles Lyons on Sept 8, 1999, wrote, “The filmmakers and Artisan’s true genius came in their prescience to treat the Internet as another vehicle for storytelling. They created folklore surrounding the Blair Witch. They added faux documents about the missing students. And, above all, they intrigued browsers.”

Variety quoted Myrick’s assessment of their phenomenal success: “We were at the right place at the right time.”