Remember when PDA simply stood for public display of affection?

In today's rapid-fire, time-deprived world, the acronym more frequently refers to the personal digital assistant — those little hand-held electronic information devices that hold people's entire lives and have become nearly as ubiquitous as cellphones. It was only a matter of time until someone built a movie around a Palm Pilot and that movie is "Little Black Book," a high-concept, wannabe dark comedy starring Brittany Murphy as a young woman who gets more than she bargained for when she peeps inside her boyfriend's Palm.

It's an irrefutably bad movie, littered with paper-thin characters, crummy dialogue and a mawkish undercurrent that wells up any time it starts to resemble something smarter and snappier. Yet it is somehow redeemed by Murphy's agreeably quirky performance in a horribly underwritten role, a better-than-it-deserves supporting cast led by Holly Hunter, and the crazily nonformulaic manner in which the story swerves in some unexpected directions.

Murphy's Stacy Holt is a seemingly happy young lady who is dating nice-guy Derek (Ron Livingston), a scout for the New Jersey Devils hockey team, and lands a job at "The Kippie Kann Show," a preliminary step on the path to her dream job of someday working for Diane Sawyer. Kippie, played with admirable moxie by Kathy Bates, is a veteran talk-show host who has slipped from prime time in New York to afternoon syndication in New Jersey, and her staff is reduced to cooking up increasingly cheesy themes ("cheerleading lesbian midgets") to goose the ratings.

Another associate producer, Barb (Hunter), takes Stacy under her wing as she navigates the increasingly slippery slope of unscripted, tabloid television. Meanwhile, the revelation that Derek once dated bulimic supermodel Lulu Fritz (Josie Maran) sets Stacy off on a quest for more withheld information about her taciturn boyfriend's past. Egged on by Barb, Stacy dives into Derek's Palm — the modern equivalent of a "Little Black Book" — which he has conveniently left behind while on a two-week scouting trip. This turns up two more women (Rashida Jones and Julianne Nicholson) whom Derek has handily omitted from his romantic curriculum vitae, and as Barb says, "omission is betrayal."

Whenever Stacy gets a little down she turns to a secret she learned from her mom (Sharon Lawrence) and puts on a little Carly Simon, whose music has a strangely empowering effect on her. In fact, there's a whole oddly cosmic connection between Stacy and Simon's music, particularly the woman-power anthem "Let the River Run" from the movie "Working Girl," apparently Stacy's favorite, which was directed by Mike Nichols, who happens to be the husband of her hero, Diane Sawyer.

Despite Murphy's comic chops and innate vulnerability that help make Stacy appealing enough, the character is far too passive to carry a movie. She's batted around like a pinball, lighting up and tallying points in reaction to what the other characters are doing but never really establishing any momentum of her own. Seeing her dragged along on a leash behind Derek's bull mastiff, Bob, while attempting to give him a walk seems like an apt metaphor for Stacy's lack of gumption.

British director Nick Hurran infuses the movie with some manic energy that keeps things moving and at times manages to gloss over the weaknesses of the screenplay written by Melissa Carter and Elisa Bell. The sequences behind the scenes of "The Kippie Kann Show," featuring Bates, Stephen Tobolowsky, Kevin Sussman, Jason Antoon and others, have an almost screwball liveliness, while Hunter brings an intensity to her role that somehow blends the calm of a Zen master and the grating edginess of someone trying to kick caffeine.

It's unfortunate that "Little Black Book" doesn't add up to more, because the movie's darker, more comic instincts might have flown with a stronger premise and better characters. The sunny "You go, girl!" sentiment and better-living-through-pop-music mantra is contradicted by the filmmakers' seeming desire to both satirize shallow immorality and live it.

Strangely enough, however, at the end of the movie I did feel an undeniable urge to run out and buy Carly Simon's greatest hits.

'Little Black Book'

MPAA rating: PG-13 for sexual content/humor and language

Times guidelines: Raunchy afternoon talk-show behavior and dog flatulence

Brittany Murphy...Stacy

Holly Hunter...Barb

Kathy Bates...Kippie Kann

Ron Livingston...Derek

Julianne Nicholson...Joyce

Revolution Studios presents a Blue Star Pictures production, released by Columbia Pictures. Director Nick Hurran. Producers Elaine Goldsmith-Thomas, Deborah Schindler, William Sherak, Jason Shuman. Executive producers Herbert W. Gains, Rachael Horovitz, Warren Zide, Craig Perry. Screenplay by Melissa Carter and Elisa Bell, story by Melissa Carter. Cinematographer Theo Van de Sande. Editor John Richards. Costume designer Susie DeSanto. Music Christophe Beck. Production designer Bob Ziembicki. Art director Peter Andrus. Set decorator Robert Kensinger. Running time: 1 hour, 46 minutes. In general release.