The '90s twist on teen idolatry is cyberspace, where Leomania is particularly evident on the teenage message boards of America Online. It is here, among the more than 30,000 current postings from young subscribers, that you can find the issues and questions that burn in the hearts of Leomaniacs. Such as:

Why is Leo so popular? Take your pick: He's hot. He's fine. He rules. He's sexy. He's cool. He's a babe. He's cute. He's a hunk. He's da bomb.Is Leo gay? Bi? Either? Neither? Both? Rumors of Leo's sexual preferences run rampant on the message boards, clearly worrying many teenage girls. "He just acts that way in movies," one muses. "Leo is not gay. He's bio!" another misspells. Many of them say it doesn't matter.

Leo is out there. Many girls post messages intended for Leo himself and assume he is reading their words. They do more than declare their love, however. They invite him home to dinner, for example, or to drop by their schools. One girl invites him to her brother's bar mitzvah.

Leo only has eyes for me. Many girls claim to have been involved with Leo, which causes many of the others to declare their outrage. "You lie girl!" is a standard response. As one points out: "If you did date him, it would have said something in the papers."

Leo spottings. Leo gets sighted more than Elvis. Girls frequently write from, say, Arkansas or Iowa, to say they saw him in a restaurant or supermarket. One girl announces that he is building a house next door to her best friend's home. Not to be outdone, another girl writes that he is building a house next door to hers.

Leo artifacts. Offers to provide Leo's home address, e-mail address and telephone number dot the message boards. None of these ever materializes. One girl claims to have one of his shoes but does not explain how she managed to acquire it.

Leo's a loser. Sometimes boys write, too.

GIRLS ARE GA-GA: The five girlfriends, ages 12 and 13, pile out of the van and bound up the steps of the Hanover Cinema. Never mind that they have already seen Leonardo DiCaprio in "Titanic" 32 times among them. Or that today is the kind of sunny spring Saturday to die for. Asked whether the day might someday arrive when they find it, you know, like boring to spend three hours watching a blond-haired heartthrob find true love but lose his life in the North Atlantic, the quintet of Scituate middle-schoolers collectively puts on a face whose message is unmistakable:

As if.

"We still always cry," Shauna Mahoney explains before the fivesome hunkers down to watch DiCaprio in "Titanic" yet again.

"Always," Heidi Gustafson agrees solemnly.

Shauna and Heidi - along with their friends Molly Hale, Christina Molinari and Laura Moore - are among the millions of young inhabitants of Leoland. It is a place where adolescents are rendered woozy by a 23-year-old Californian with limited acting skills and terrific eyes. In the tradition of Sinatra, Elvis and the Beatles, the star whom the teen mags invariably refer to as Luscious Leo or Delicious DiCaprio persists in capturing most of the young female hearts in sight.

Although "Titanic," DiCaprio's blockbuster 10th feature film, was released four months ago, the actor has turned out to be considerably more unsinkable than the ship. In a media world where specialized magazines, quickie bios and online connectivity quicken the heartbeat of teenage idolatry, Luscious Leo seems to be everywhere at once.

Just look. DiCaprio's face graces the covers of no fewer than four current issues of magazines aimed at teenagers. (Seventeen magazine has two separate and simultaneous Leo covers, the first time this has happened in the publication's 54-year history.) Three books about him are currently resting among the six hottest paperbacks on The New York Times best-seller list. Meanwhile, on the teen message boards of America Online, there are more than 30,000 postings from young subscribers pertaining to DiCaprio. The next highest number for any star, teenage actor Jonathan Taylor Thomas, is 15.

Small wonder that DiCaprio - whose 11th movie, "The Man in the Iron Mask," is also currently in theaters - receives an average of six bags of fan mail a day, according to his publicist, Cindy Guagenti. "The interest," Guagenti muses, "just isn't calming down."

NO. 1 HEARTTHROB: Christina Ferrari is the managing editor of Teen People, a Time Inc. offshoot of People magazine that was launched in February. She previously spent three years editing YM, another magazine for teenagers. So, although she's in her early 30s, Ferrari knows her teenage heartthrobs. "Leonardo," she says, "has blown away every teenage idol of the last 15 years in terms of intensity and in-ter-est."

The most intense and interested fans are 12- to 15-year-olds, Ferrari points out. "They're acting out their fantasies and crushes," she says. "Older girls are dating real boys, but these younger girls don't date yet. So they're daydreaming about dating Leo."

But why Leo? "He's the perfect boy/man," Ferrari replies. "He's not threatening. He's sexy but sensitive. He's masculine but still romantic. A lot of young teenage girls fantasize about having a boyfriend who can also be their best friend. Leo, and the role he plays in `Titanic,' is just that. Young teenage girls are looking for models of a relationship, and he's their model."