Joseph Griffin, 43, of Hartlepool, County Durham, faced court this week for a Facebook post that called another man a paedophile. He pleaded guilty and was fined for sending the offensive message - which he said he did out of anger and frustration.
It underlines the importance of serious thought before taking to the social networks.
The caseGriffin updated his status to include the claim about another man - which also included his name and address. The message was up for 90 minutes in the middle of August before he deleted it.
The prosecuting lawyer said: "Mr Griffin told police that he had a Facebook account and admitted he had put comments on about this man because he was angry and frustrated."
Griffin pleaded guilty to sending by public communication network an offensive, indecent, obscene, or menacing message or matter. He was fined £50, ordered to pay £85 costs and a £15 victim surcharge.
The risksIt's the latest in a long line of cases which highlight the dangers of posting your views on social networking sites without understanding the risks you are taking.
There have also been those jailed for malicious tweets, including 21-year old Liam Stacey - imprisoned for his Tweets about footballer Fabrice Muamba.
The lawThe law is very clear. Any social media update which would lower the average person's view of someone, or make them feel threatened or distressed, is punishable by law. And increasingly, these cases are coming to court.
Richard Moorhead, Professor of Law and Professional Ethics at UCL, and Director of the Centre for Ethics and Law told AOL: "The courts are starting to grapple with social media. They are seeing it as an emerging problem and are giving every signal that they are taking it very seriously."
He warns: "People need to be careful that what they say is truthful and fair. They should follow basic rules of common sense. If you're honest and not rude about other people then you're not generally going to be in any trouble. It's easy for people to get carried away, but they need to take time to calm down before they post anything online."
The advice is therefore to think very carefully before you post. Is your post offensive, could it upset someone or open them to ridicule? And if in doubt err on the side of caution. If you don't have anything nice to say, don't say anything at all.