The linguistic acrobat
How to identify Answers Facebook quizzes ("What kind of toothbrush do you use?") as though he were interviewing at the New Yorker, complete with convoluted sentence structure and obscure pop-culture references.
What to do when you spot one One-upmanship. Or hire a surrogate to humble his pompous ass in Scrabble.
How to identify This person simply "is" . . . unable to operate a BlackBerry.
What to do when you spot one E-mail him a titillating Zen koan — replete with un-openable attachment.
The loose cannon
How to identify Becomes incensed by one of your posts and surfaces from the depths of obscurity to reprimand you. For instance, you write: "I just had a disappointing brunch, discovered a fly on my lox." This jerk responds with charges of anti-Semitism.
What to do when you spot one Nothing you could say or do will pacify him. Take solace in the fact that, from the look of his profile, he lives alone with overflowing litterboxes, writing unpublished letters to the National Review.
The nut job
How to identify Generally, someone who went insane since you last crossed paths. He's living in the forest, seeking peace and solace, and has simply reached out to wish you the best on your spiritual journey.
What to do when you spot one Wish him a blessed day, then pray that woodland creatures destroy his Internet connection.
How to identify This woman, who always gave you weird passive-aggressive vibes in real life, feigns social niceties online by being the first to congratulate you on the new job, to console you after a bad day, and to offer pleasant commentary on your wedding photo album. What the hell is she trying to hide?
What to do when you spot one Reply in kind, with as many exclamation points as possible, until you can no longer live with yourself. Then de-friend her.
How to identify Slightly more dangerous than the Compensator, the Liar is etched in your memory as a malignant classmate who once stole your boyfriend. Now, she's so happy to see you on Facebook! She thinks your ramshackle home in the middle of nowhere is super cute! She just happens to work nearby and would love to meet up for drinks!
What to do when you spot oneRendez-vous looking better than you've ever looked. If that's not a realistic possibility, immediately enter the Witness Protection Program.
How to identify This person, perhaps a parent, is generationally unequipped to post clever, pithy thoughts in a digestible format. Status updates ramble on for paragraphs; wall posts resemble a Christmas newsletter. Each missive is signed with a full name.
What to do when you spot one Distract mom with a new piece of technology, like a digital camera or a Vera Bradley purse.
How to identify Here's somebody with an inner monologue so dull you want to cry. "Just paid my phone bill!" "What a great night's sleep!" "I'm watching birds mate!"
What to do when you spot one Hand 'em a line of cocaine and a shotgun.