A smart, melancholy subculture slice-of-life and an unromantic roundelay between half a dozen denizens of the internet underground, the stylish low-budget indie "On_Line" has serious art-house sleeper-hit potential.

Taking place in large part over the internet (through webcams, QuickTime windows and creative split-screen effects), the interwoven stories revolve around a cybersex web site called Intercon-X, operated out of the sparse Manhattan apartment of two recent college grads.

Harmless, insecure, broken-hearted, cynical John (unshaven, sad-eyed Josh Hamilton, "The House of Yes") and charismatic downtown lothario Moe (Harold Perrineau, "The Matrix Reloaded," HBO's "Oz") don't seem to be making a fortune, but the site has become the primary source of human interaction for most of the film's damaged and cautious characters.

Having been thrown over by his fiancée, John is both in the dumps and in denial ("She hasn't given the ring back," he insists) as he strikes up an on-line-only dominant-submissive relationship with sultry young Jordan (Vanessa Ferlito), one of Intercon-X's on-call fantasy girls. But when they meet in person, having discovered they live only blocks away from each other, John promptly goes down in flames.

In fact, in the middle of a double-date, Jordan slips off for a nightclub-bathroom quickie with Moe -- a fact that Moira (Isabel Gilles), Moe's very temporary but desperately clingy and quick to say "I love you" girlfriend, discovers when logging on to the compulsively blunt, woe-is-me video blog that John's posts on his own web site daily.

Character- and dialogue-driven in a way that's reminiscent of a less high-minded Whit Stillman ("Metropolitan," "Barcelona," "The Last Days of Disco"), "On_Line" is a savvy, shrewd commentary on the listless self-absorption of modern computer cocooners. (It's also a very different experience from the similar Thomas In Love, a futuristic French film from 2001 shot entirely from the point of view of a internet-addicted shut-in.)

The already unstable Moira is sent into an emotional tailspin that she describes only to Eddy (Eric Millegan), an online pal from a suicide support site. Eddy, of course, has troubles of his own that he can't share in the real world -- he's a frustrated, fretful gay virgin college freshman trapped in hetero small-town Ohio. And the movie's six-degrees circuit is completed by Al (John Fleck), a 40-something Intercon-X sex worker who is Eddy's fantasy outlet and Jordan's mutual confidant -- two relationships that are more complex than you'd suspect since they're both based entirely in the ethers of the internet, at least at first.

Co-writer and director Jed Weintrob juggles and connects his characters in a dexterous mishmash of computer screen and digital video imagery that gives the picture a lively edge (enhanced by a memorable soundtrack of alternative music), and the unaffected performances candidly capture raw anxieties, instabilities and sexualities. (Being a movie that revolves around online sex, there are a lot of hands down skirts and pants.)

The outcome of one of the film's relationships is a bit too obvious, and another is a bit unlikely. But Weintrob's story arc is deliberately incomplete in a way that leaves one's interest piqued as the credits roll. Characters that are paired off don't seem psychologically healthy enough for these relationships to last -- and maybe they're not supposed to.