You may have seen the phrase 'check your privilege' being hurled about online. But what does it mean? Is it just a way to shut down people who disagree with you – or a means to open up the debate?

It may sound like a quote from the film Clueless, but laugh at your peril. The command "Check your privilege" has become one of the great political rallying cries of 2013, and if you haven't heard it yet, you soon will, because it is fast slipping over from the social media sites – where it has become a clamorous chorus this year – to the mainstream media, largely thanks to journalists and certain former politicians who profess themselves to be baffled by its meaning.

To be fair to them, its meaning is not always obvious, because all too often the well-intentioned phrase is abused. But roughly speaking, it is a way of telling a person who is making a political point that they should remember they are speaking from a privileged position, because they are, for example, white, male, heterosexual, able-bodied or wealthy. It is, in other words, a sassy exhortation to acknowledge identity politics and intersectionality (the school of thought which says, for example, that different minorities experience oppression differently). So for example, if a white, female journalist tweets that she "literally could not give a shit about" the representation of black women on Lena Dunham's TV show Girls, she will face a chorus of tweets telling her to "check her privilege". Or if a former Tory politician writes a comment piece saying feminists should not get so bogged down in fights about identity, she will be told to check her privilege. Or if a white, male journalist writes a blog for a rightwing newspaper's website sneering at the concept of privilege-checking, he will be told to – OK, you get the picture.

Caitlin Moran gave feminism a boost with her book How to be a Woman, but has also been attacked for failing to check her privilege. Photograph: Martin Argles for the Guardian

The command to check one's privilege might feel ubiquitous now to those who spend too much of their days on social media, but in fact the phrase has experienced a slow burn. The first use of it was in 2006, on the social justice site shrub.com, when a blogger calmly wrote about how everyone to a certain extent speaks from a position of privilege and they should take into account that others are not as privileged as them. You can date the phrase back further, to 1998, when Peggy McIntosh used the word "privilege" in her essay White Privilege: Unpacking the Invisible Knapsack. But it was really shrub.com's post that coined the phrase and established the still current usage. Slowly, the phrase started appearing on blogs – often feminist ones – and, as far as I can tell, the Guardian (take a bow, Guardian!) was the first national newspaper to use it last year.

So far, so what, really, right? Well, now we get to the fun bit of check-your-privilege's story, when it stopped being a calm, thoughtful and still faintly academic phrase, and became the subject of ferocious debate among, first, those on the left and, now, those on the right.

First, it is important to remember we are dealing with interactions on social media here, a medium that is to "calm" and "thoughtfulness" what the Daily Mail is to reasoned political debate. So when journalist Caitlin Moran said she "literally couldn't give a shit" about racial representation on Girls, she was bludgeoned with commands to check her privilege to a degree that veered on bullying. Many on the left complained that the phrase was too often being used to shut down debate; those who used it said the complainers were merely upset at being called out on their failings. For the first half of this year, it looked as if the quarrel was merely among those on the left, reflecting issues of, equally, liberal elitism and liberal guilt. The growing interest in feminism in the media – aided in a large part by Moran's book, How to Be a Woman – also kept the phrase in constant use, with some feminist bloggers arguing hotly among themselves about the merits or otherwise of intersectionality in feminism.

Laurie Penny defended 'privilege-checking', saying: 'Telling someone to "check their privilege" isn’t the same as censoring or silencing.' Photograph: Ken McKay Rex Features

These debates became so vocal that it was inevitable the phrase would soon be noticed on the either side of the political spectrum and, boy, hasn't it just. Last week, former MP turned fashion blogger Louise Mensch wrote an excoriating piece that ran on the Guardian website claiming that British feminists spend their time arguing about "privilege checking" whereas "American feminism gets organised". This came as something of a surprise to anyone who knows that the concept of privilege-checking and intersectionality originated in America. One can only assume that Mensch hasn't spent too much time on any US campuses if she thinks American feminism doesn't engage in identity politics. Anyway, as seems to be the way with modern media now, writer Laurie Penny then wrote a column in response defending privilege-checking and the whole thing became a pan-political, multimedia bunfight.

According to Mensch: "'Check your privilege' is a profoundly stupid trope that states that only those with personal experience of something should comment." According to Penny: "Nobody's telling you to shut up ... Telling someone to 'check their privilege' isn't the same as censoring or silencing." In truth, both women are right and wrong. Yes, Penny is right that "Check your privilege" is, at root, a benign concept, but Mensch is right that sometimes it is abused and misused in a way to suggest that personal experience trumps all. But that doesn't mean that every time it's used it is irrelevant.

It is easy to mock privilege-checking, with its inferences of loony leftiness and pulsating liberal guilt. Yet it's just as easy for certain media figures to forget that theirs is not the only voice that matters. Ultimately, a well-meaning reminder to listen to other people occasionally has been turned into an angry cliche through misunderstanding, mockery and overuse. Maybe it's time for the phrase itself to check its privilege.