1. Paul Chambers and Robin Hood AirportFamously, trainee accountant Paul Chambers was frustrated on a plane and said on Twitter that Robin Hood airport ought to be blown up as a result. He didn't mean it of course but ended up in court - only last week the appeal court reserved judgement on the case. Moral: Don't make jokes about bombs on Twitter.
2."TheConner" and Cisco"Cisco just offered me a job! Now I have to weigh the utility of a fatty paycheck against the daily commute to San Jose and hating the work." So said a Twitter user called TheConner a few years ago, which Cisco saw. Funnily enough it withdrew the offer of work. It may seem obvious, but don't insult your employer where they can see it.
3. McDonalds and McDstoriesBurger giant McDonalds tried offering a human face by tweeting about its suppliers using the #McDstories hashtag. Unfortunately detractors soon adopted the hashtag and started putting stories of their very worst experiences in the restaurants online.
4. Kenneth Cole and the Arab SpringDesigner Kenneth Cole personally tweeted, 15 months ago, "Millions are in uproar in #Cairo. Rumor is they heard our new spring collection is now available online at http://bit.ly/KCairo -KC". People were furious, he apologised and withdrew it, but on the internet things tend not to go away.
5. Stuart MacLennan, Labour candidate at the last election...or he was until he Tweeted: "God this fairtrade, organic banana is s**t. Can I have a slave-grown, chemically enhanced, genetically modified one please?"
6. Fearne Cotton at the JubileeFacts: Fearne Cotton is a TV presenter of some experience. Other fact: Not everybody liked her approach to the Queen's Jubilee. The sensible thing to do is to take it on the chin - you put your head above the parapet, people have the right to comment. What you don't do is put ripostes up like: "People who sit lazily and judge others will never grow. They'll never take a look at themselves or feel content. Shame so many do," nor do you say: "Grown men who slag me off in articles/online are huge bullies. I love my job and wouldnt be doing it if i wasnt any good at it."
There's a simple rule: if you say these things out loud even your fans will stop agreeing with them. By contrast, when Jonathan Ross was still on the BBC's film programme a 'fan' told him on Twitter that he should stop, it was boring. Ross simply Tweeted back "I'd just watch something else if I were you." Dignified and not defensive - also what everyone else was thinking.
7. VodafoneOffice junior puts out a homophobic Tweet which Vodafone subsequently apologised for. There should be a whole section on office juniors - or more particularly on companies letting their interns or junior members of staff handle the Twitter account unsupervised then wondering why it goes wrong.
8. Starbucks and the IrishOver the Diamond Jubilee weekend (which wasn't a bank holiday in the Republic of Ireland), Starbucks invited its 2,000 Irish followers to say what made them "proud to be British". A wave of consternation followed before Starbucks apologised, blaming a technical hitch (posted to the wrong Twitter account).
9. Chrysler AutosThe car company claimed its account had been compromised - in fact it had outsourced to an agency - when it published the Tweet "I find it ironic that Detroit is known as the #motorcity yet no-one here knows how to f***ing drive."
10. Charlie SheenWe wouldn't know where to start with this one - perhaps just to say if you're genuinely unwell, as would appear to be the case, you can only hope someone will help stop you acting your condition out in public.
Blogger Guy Clapperton is the author of "This Is Social Media"