A documentary that opened recently in major U.S. cities on the brief but intense life of Napster should reinvigorate debate about why such a revolutionary technology has never again reached the mainstream, even if the movie gives too pat an answer.

Backed by music video channel VH1 and appropriately available online, “Downloaded” reunites former teen founders Shawn Fanning and Sean Parker in a bid to educate those too young to remember 1999.

The film is a valuable one. Fanning sold the rights to his fascinating but little-understood story for what became this project a decade ago and hasn’t told much of his experience since. Parker became a billionaire thanks to his Napster-influenced early role at Facebook and continues to obsess about music: He is now an active director and investor at streaming service Spotify.

Directed by Alex Winter, best known as Bill from Bill & Ted’s Excellent Adventure, Downloaded gets a lot of the details right — Napster’s origins in an online hacking group frequented by budding criminals, the exuberance and technical challenge of scaling to serve 40 million users, and the famed but private startup’s takeover by lawyers.

More importantly, it captures the energy of the vital few months when technology became cool for teenagers, when a poor kid from outside Boston used some of the basic principles of the Internet to deliver seemingly all recorded music to everyone for free.