Directed by Ariel Schulman, Henry Joost. Starring Nev Schulman, Angela Wesselman-Pierce, Ariel Schulman, Henry Joost 12A cert, IFI/Light House, Dublin, 86 min

A SUNDANCE winner and something of a water-cooler sensation, this highly suspect documentary is certainly not short on talking points. At a time when plenty of decent-minded, accomplished reality portraits ( Billy the Kid, Steve) are unfairly criticised as "freakumentaries", Catfishis the real deal.

A warning shot from Web 2.0, the film follows co-director Ariel Schulman’s brother Nev as he embarks on a star-crossed Facebook romance. A complicated evolution of clicks ensues: over the course of several months Nev befriends the Pierces, a Midwestern family whose eight-year-old daughter, Abby, sends him a painting based on one of his ballet photographs. As Nev and the young prodigy exchange more and more photos and artwork, he befriends Abby’s mom, Angela, then her dad, Vince, and soon enough, the whole extended family.

Nev’s interest in the Pierces is further piqued when Abby’s grown-up half-sister Megan adds him to her directory of online friends. A gorgeous singer and model, Megan may well be the girl of Nev’s dreams.

Fear of the spoiler police prevents us from revealing anything more. Suffice it to say, one shouldn’t put too much store in Facebook profiles.

You can see the appeal for the picture's headlining producers, Capturing the Friedmansdirector Andrew Jarecki and blockbuster jobsworth Brett Ratner. It's ripped from today's headlines. It's controversial. It's the stuff of urban legend. But reader, we didn't buy a word of it.

We're pretty sure the people in the film exist and that something similar to the events depicted did occur. And we're pretty sure that social networking sites are out there. Beyond that, Catfishsmacks of entrapment and restaging.

If the film-makers are to be believed, they are the victims of an elaborate hoax. It’s far more likely that their subject was groomed in turn. Throughout, there are small caveats, like who on earth embarks on a social networking romance without googling the object of their affection? There are considerably bigger ethical issues.

Schulman and Joost must be congratulated on their scoop, however they might have procured it. But as documentarians they fail to ask even the most basic questions. Their subject, meanwhile, is the genuine talent behind the picture. And for that, they are ridiculed by a bunch of callow New Yorkers with cameras.

Entertaining, exploitative, dubious, like The Social Network, Catfishis a mean-spirited movie for a mean-spirited age. See it. Fight about it. Believe the hype but not the picture.