The Facebook community has been under silent attack for the past few months, and the evidence is plastered all over the Walls. Careful observers have probably already spotted a few of these malignant growths on their Newsfeeds: posts that look something like Zack Newick, Giri Nathan and 15 other friends like “OMG Justin Bieber Really said that ?!!”

Depending on how naïve and/or inquisitive you are, you might be tempted to click the link yourself—a number of your friends have gone so far as to “like” it, so it could be worth seeing. Another window will pop up, and it won’t be Facebook. This window might look suspiciously like a YouTube page, but a bit off (like a cheap mockup coded by an enterprising teenager somewhere in an Eastern European Internet cafe), and it will ask you click a play button to start the juicy video. Or it might be a blank screen, inviting you to “Click here to continue.” Either way, you obediently click away. Herein lies your fatal error: as soon as you click you’ve unwittingly published at a post on your Wall telling people that you too like “OMG Justin Bieber Really said that ?!!” Often you will find that you never even get to watch the video that lured you there in the first place, because it never existed. Then comes the tragic snowball effect: your like will surface on all your friends’ Newsfeeds, and they too will click it, and it’ll appear on their friends’ Newsfeeds, and this whole inane and inscrutable thing will spiral out indefinitely, social media-style.

This benign form of scamming has been dubbed “likejacking,” because it dupes you into liking something you never intended to. The technique is actually somewhat clever: the scammers create an invisible web object, which, when clicked, triggers the like on your Facebook account without your knowledge. Effectively, they’ve stretched one big invisible Like button over the entire page, so you’ll never know which layer you’re clicking on (although you can hover your cursor around the page and check to see if it changes into that pointer hand that indicates clickability). Thus they harvest all of our gullible clicks. Likes are precious Facebook commodities, because the more likes an item has, the more likely it is to appear on Newsfeeds.

Fully aware of that fact, these scammers play off our basest curiosities. They hawk videos of the irresistible—which is to say, things that are extremely unlikely or mildly salacious. Some classic examples include “LOL This girl gets OWNED after a POLICE OFFICER reads her STATUS MESSAGE” and “The Prom Dress That Got This Girl Suspended From School.” Teen pop star slander is another prominent motif. And sometimes they riff off current events; I spotted one last week that promised exciting never-before-seen footage of the Japanese tsunami, which seemed tasteless even by Internet scam standards.

What is particularly bizarre about this fraud is that the scammers don’t seem to get anything tangible out of it. Unlike your friendly Nigerian email acquaintances, there’s no cash money involved, no dubious transaction; the only possible negative consequence is the embarrassment of having fallen for it. Most troubling is how boldly it breaches an essential tenet of the Internet: the freedom to click a link about Justin Bieber in the comfort and privacy of your own browser without broadcasting it to the world—or at least the Facebook community, if those two things aren’t quite synonymous (yet).

There are failproof ways to avoid getting hoodwinked. You can download a tool that alerts you whenever invisible objects appear on the page. But there’s an easier and less technical way to go about this: a healthy dose of skepticism. By following a few basic principles, I’ve never fallen for one of these (except when researching this article), and I have distilled my thought process into a few questions that you can ask yourself the next time 34 of your friends like some link that contains “LOL.” That way you can hold on to your dignity, preserve the sanctity of your Wall, and spare your friends from this unsightly Newsfeed plague.

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Look carefully at the link name:

Is it taking you to a website called “horriblejapaneseearthquakes.info” or something equally preposterous?

Is it riddled with spelling errors?

Are there unnecessary spaces ?

Are words aggressively Capitalized Like THIS?

Are there unintelligible bursts of consonants that might belong to some other language, a language that a scammer might use?

Consider the people involved:

Have a suspicious number of people already liked it?

Has it already been liked by people who are liable to fall for Facebook scams?

Has it already been liked by people in less Facebook-savvy demographics (e.g. under 13 or over 35)?

Think about what it’s offering:

Is it promising to show you something that is patently impossible?

Is it something that would’ve already appeared on a more reputable website if it were actually true?

If you look at the thumbnail photo, is it some stock image that would come up if you googled the relevant words?

Is it The Best Handball Penalty you’ll not ever and never seen !

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In the unforunate event that you do end up succumbing to one of these scams, promptly delete the story from your Wall. It may also have infiltrated your Likes and Interests section, so be sure to check there as well. Your likes (not unlke your days) are numbered, and they are to be treasured. You can’t afford to lose them to the scammers. Facebook safely.