Here are 10 species of Internet troll I've observed and cataloged in my study of the Wild, Wild Web. Recognize them. Avoid them. Lead a much happier life without them.

1. Stalkers. Attention seekers who need others' responses to feel validated. They follow you from one page to another, leaving comments on whatever you post. The problem is, you never know whether to treat them like lost puppies and scratch behind their ears, but this just keeps them coming back for more.

2. Lurkers. The next stage in the stalker's (d)evolution. Having been banned or blocked, they stay quiet and hide behind bogus profiles, conducting online espionage. Like the rude but distant relative who invites himself to Thanksgiving dinner, they feel they're entitled to a place at the table, even after they've been asked to leave.

3. Imposters. Critics who masquerade as a member of a certain group, they wait until the time is right, then ambush members in an open forum - sometimes with self-righteous religious rhetoric, sometimes with ads for fake Ray-Bans. I'm not sure which is worse.

4. Backstabbers. They air their dirty laundry to the world, slamming a spouse, relative, "friend," boss or some other third party who's (conveniently) not around to defend him/herself. They smile in your face. All the time, they wanna take your place ...

5. Know-it-Alls. These ego-driven types pose as authorities to gain "minions" as though they'd been chosen for the lead in Despicable Me - even though the lead character in that animated film is far more three-dimensional. Like stalkers, they want validation. But instead of targeting a single person, they cast a wider net in an effort to build a cult-like following. They're usually not authorities on much of anything. But that doesn't stop them from pontificating ad nauseam on their favorite subjects.

6. True Believers. The minions or clones from No. 5, who follow Know-it-Alls pretty much blindly, faithfully memorizing their scripts and robotically regurgitating their lines. Clones? Dittoheads? Do people actually take pride in these labels? Sometimes the Web is far too similar to bad talk radio, and you've just change the station.

7. Button-Pushers. They get a rise out of people by posting uncompromising positions on hot-button issues. On the one side, they get a lot of attaboys; on the other, they receive plenty of criticism (often spiced up using colorful language). Either way, they're out for attention, same as the Stalker and the Authority. They're motto: All publicity is good publicity.

8. Victims. Often Button-Pushers who pretend to be persecuted for their beliefs, they fly the "minority" flag as though it were a battle standard - whether or not they're actually in any minority. One favorite tactic: saying something outrageously offensive, then crying "censorship!" when the owner of the wall or page removes their comment.

9. Advocates. People who take up a single issue or slate of issues and draw a life-or-death line in the sand, then dare others on Facebook to cross it ... which, of course, they do, leading to sometimes amusing but mostly aggravating repercussions. They produce more litmus tests for than your eighth-grade science teacher and flunk you if you answer one question in a hundred the "wrong" way.

10. Devil's Advocates. The people who fuel the Button-Pushers' fire, their goal is, like most of the others, to gain attention - but their method's a little different. They're counter-punchers. They wait for someone else to state an opinion, then look for a weakness and pounce when they think they've found one. It's purely a game of one-upmanship. The Devil's Advocate who can beat the Know-it-All in an argument has pulled off an effective Facebook coup and can build a following of his/her own.

Illustration: John Bauer, from Walter Stenstrom's The Boy and the Trolls or The Adventure in children's anthology Among Pixies and Trolls, a collection of children's stories, 1915 (public domain image).