If all of life is like high school, at last we have the answer to the question that goes to the core of our id-driven, zit-popping, green-eyed insecurity:

Are you more popular, at this very second, than the person who's instant-messaging you?

Instant messaging, you will know, is the way tens of millions of Americans connect with their buddies faster than e-mail. Beginning this week, the 50 million users of AIM, America Online's version of instant messaging -- including nearly half of all Americans between the ages of 13 and 25 -- could perform a self-esteem check by visiting www.aimfight.com. There you enter your AOL or AIM screen name and your friend's AOL or AIM screen name. Then you click "fight" to figure out who's got a bigger score -- as in who's better connected and more popular. You can almost hear the tap-tap-tapping on the keyboards right now.

Your popularity is based on who has you on their buddy list. There's a complicated algorithm at work here. Your score is measured to the third degree, in the sense of the "six degrees of separation" game that seeks to link anybody on Earth to any other person through no more than five friends.

Say a couple of your friends, A and B, have you on their buddy lists. A, who has three people on her buddy list, doesn't add much to your score. That's because she doesn't have as many people on her buddy list as does B, who has 16. Your friend A is clearly not as well-connected as your friend B.

Not unlike life.

Online popularity is the state-of-the-art measure of vanity. There are several thriving communities that trade on how linked-up you are. They include the Facebook (www.thefacebook.com), an interactive yearbook that aims at the college crowd; Friendster (www.friendster.com), a more general place, like a downtown bar, to meet friends, co-workers and strangers; and MySpace (www.myspace.com), a do-it-yourself, all-around-service where you can blog, post pictures, etc.

Never mind that Yogi Berra once said that "anyone who is popular is bound to be disliked"; Mark Twain, after all, summed it up fine: "He liked to like people, therefore people liked him." In spite of that quiet but quaint voice in your head that says you shouldn't care how you stack up, of course you do.

"May it be online or offline, wherever, it's always about someone you know who knows someone else," says Chamath Palihapitiya, AOL's 29-year-old vice president and general manager for instant messaging, who speaks in a calm, unhurried voice that carries an air of someone who knows quite a bit about socializing. Because of the popularity of buddy lists, he adds, AOL last month decided to increase the number of people allowed to be on a user's buddy list from an impressive 200 to an astonishing 450. (Yahoo and MSN also offer instant messaging, although their versions are not as popular as AOL's in the United States, nor have they yet matched the new popularity fight feature. Their buddy lists are not taken into consideration by AimFight.)

"You can't affect your own score," says Palihapitiya. "The only way you can increase your score is to convince people to buddy-list you."

Around 2:30 in the morning Tuesday, a 50-year-old divorced computer trainer from Centreville is chatting on "Virginians over 40" at AOL.com. She wonders if she's more popular than her recent ex-boyfriend. "This is a nice little diversion," she says of AimFight. She's got "only 11 people" on her buddy list, she says, and she's "not sure" how many people her ex has on his.

Nonetheless, she types in her screen name and the screen name of her ex. "I won the fight, so it looks like he is not a lady's man, maybe?" crows Lydia, who repeatedly declines to give her last name out of embarrassment -- "What's a 50-year-old doing chatting in the middle of the night?"

Jordan "Jord" Vogt-Roberts, a 20-year-old film major at Columbia College Chicago, is part of that rarified company with more than 200 people on his buddy list. He has divided them into five categories that he calls "defcons."

"I was such a geek in high school, really big into conspiracy theories, and I think 'defcon' is a Department of Defense term," says Vogt-Roberts. "Defcon 1 is where I keep my four really good friends. Defcon 2 is about six people who I talk to on a regular basis. Defcon 3 to 5 are just randomly placed people I don't talk to very much."

Like so many people his age, Vogt-Roberts has had an AIM account since junior high. He prefers speaking face-to-face above all forms or communication, he says, but would rather instant-message than talk on his cell phone. When his family relocated from Royal Oak, Mich., to Mesa, Ariz., after the eighth grade, he kept in close contact with his buddies Matt ("the one who's really into metal music"), Tony ("the super witty guy"), Jon ("the artist of the group") and Jeremy ("the group's philosopher") through AIM. Before his senior year in high school, he moved back to Royal Oak.

So far, while chatting on AIM, he's "fought" against two screen names on AimFight.com -- his ex-girlfriend Kelly (he lost) and his friend Matt (he won).

"The more I played with it, the more it definitely had this neat little voyeur element to it, a nice little competitive element," says Vogt-Roberts. "It's a fun gimmick."

He types in five more screen names. "Well, if you think about it, the way this whole AimFight thing works, your worth is measured through other people." He realizes that he's only talking about instant messaging. "That's kind of messed up," he says. Then he types in two more screen names, testing their popularity.

Sitting in the smoke-filled SoHo Coffee House west of Dupont Circle, Ryan Jackson is doing what he does often: Web-surfing. In the course of five minutes or so on his laptop, he ranges from an article on "The Da Vinci Code" in www.christiantoday.com, to checking out Facebook, and then talks about AimFight.

"I'm sure plenty of people are getting a kick out of this," says Jackson, 19, biting on a chocolate croissant. He's had AIM -- "um, what, for like forever?" he says -- since he was 12 and has 62 people on his buddy list. Right now, 18 of his 62 friends are online. He types in his screen name and a friend's screen name. He wins. "I don't feel the need to judge my social standing," Jackson goes on, "by how many people I talk to, or talk to me, online."

Then he closes his AIM window, only to open it up again a few minutes later.