Sickipedia, the site where the young Lancashire man Matthew Woods found inspiration to post "jokes" about the missing child April Jones on his Facebook page was "down for maintenance" when I tried to check it out this morning, though I managed to get a glimpse of the kind of content it publishes courtesy of Twitter.

I'll reproduce just one, which should come with the equivalent of one of those taste and decency disclaimers you get on TV: "My dick is a lot like Marmite. My wife hates it when I rub it on her toast". That was from May. That alone should allow you to conclude, if you hadn't already realised from its name, that this site is for the seriously sad and inadequate. That should be the end of the story. The decision of Woods, however, to reproduce "jokes" about April Jones and Madeleine McCann has led him to be sent for 12 weeks to a young offenders' institution. Prior to that he had been taken into protective custody to prevent him being lynched.

Woods pleaded guilty to sending by means of a public electronic communications network a message or other matter that is grossly offensive. In mitigation, his lawyer cited a "moment of drunken stupidity", but the presiding magistrate said the comments were so "abhorrent" he deserved the longest sentence the court could hand down. The Crown Prosecution Service confirmed it had reviewed the file and was content with the prosecution going ahead.

Woods's case is by no means an exception. The CPS is currently reviewing its approach to social media in the light of several cases in which substantial sentences have been handed down after people have posted offensive remarks on Twitter and Facebook or sent them directly via email.

These cases have included the 56-day jail sentence for the student who tweeted offensive and racist comments in response to the on-pitch collapse of the Bolton footballer Fabrice Muamba. The latest example is the case of a young man who has been sentenced to a community order for posting the message "all soldiers should die and go to hell" on Facebook after the death of six British soldiers in Afghanistan.

Perhaps the highest profile case is still the "Twitter joke trial", when 28-year-old Paul Chambers was found guilty of sending a "menacing" tweet for threatening to "blow up" Robin Hood airport near Doncaster after it was closed by snow. That conviction – in a case ridiculously pushed by the CPS – was quashed in the high court, but only after a prolonged legal battle in which he was supported by a number of celebrities.

The judgment that day set what seemed like a new benchmark: "If the person or persons who receive or read it, (the message) or may reasonably be expected to receive, or read it, would brush it aside as a silly joke, or a joke in bad taste, or empty bombastic or ridiculous banter, then it would be a contradiction in terms to describe it as a message of a menacing character."

This was not a case of anything goes, the judges implied, but be careful not to mistake stupidity – no matter how offensive the remarks might be – with criminality.

The same surely applies to the Sickipedia story. Direct incitement to violence is one thing. But we cannot and should not sentence people for bad jokes, poor taste and terrible manners. That is an issue for parents, teachers and, most importantly, peer groups.

In late July, police visited a teenager in Weymouth after he had posted an abusive tweet about the Olympic diver Tom Daley. I commented then that the best response from Daley (who had retweeted the offending missive) and the authorities would have been no response at all. This, I suggested, was the online equivalent of the boy on the park bench or the bore propping up the bar in the pub.

The following day I received an email from a chief constable thanking me. Law enforcement, he suggested, should get on with investigating serious crimes.