It’s true, though, isn’t it? I’ve kind of got used to the fact that most people who post comments on Internet forums or newspaper articles can’t spell, or punctuate, or construct a grammatically correct sentence, or follow a logical argument. But I’m still constantly amazed by the number of people who don’t get even simple jokes.

I long ago realised that most people don’t get irony. Joe Queenan regularly writes heavily ironical comment pieces for The Guardian, which are generally met with bafflement and outrage by posters on Comment is Free. His biggest failure in this regard was an article called How satire changed the course of history – a satirical piece that argues that the role of satire in influencing political opinion is overstated, an argument that fell on resolutely stony ground. In fairness you could argue that the entire article is self-defeating and Queenan deserved what he got (mostly abuse).

It’s Caitlin Moran I feel sorry for. In addition to her very funny column in The Times, she writes occasionally posts for AlphaMummy, an ironically-titled (I hope, anyway), blog aimed at working mothers. Her posts are generally amusing snippets of family life, and they are actually funny in a true-to-life way, as opposed to the “Oh, look at ditsy old me, I’ve gone out in my business suit with baby sick on my shoulder” kind of humour that tends to pervade the working mummy genre of journalism.

But hardly any of the people who post comments get the jokes. This week she wrote a short piece called “The worst thing I ever heard a child say” , about a girl in the school playground who wouldn’t let the other children join in a game unless they had Sky Plus.  Caitlin refers to the girl as “Barbara” (“I like to refer to all bad children as 'Barbara’”) and says that after her daughter related the incident to her, she “sat both the kids down, read them the entire works of Marx, and then made them say ‘Barbara is a pitiful, corrupt, running dog of capitalism’ nine times before bed.”

This prompted a series of comments on the following lines:

1. This is very unfair to people called Barbara. What have you got against the name “Barbara”?
2. You are just a Murdoch lackey trying to promote Sky Plus.
3. Only working-class people have Sky Plus, so you/Barbara have got it all wrong.
4. Socialism is evil.

My favourite comment, I think, was “I assume the bit about Marx is a joke. How sad would you be if you were indoctrinating marxism to carefree children.”

Oh yes, indeed. Either it’s a joke or Caitlin Moran really read the entire works of Marx – including the three volumes of Das Kapital, the Communist Manifesto, the Eighteenth Brumaire of Louis Bonaparte, and the rest – to her two primary age children. In one evening.

So, poor Caitlin Moran. It must be really dispiriting to write something you think hits exactly the right note – light, funny, mildly self-deprecating – only to discover that no-one gets the joke.