American Justine Sacco, a PR executive for an internet company, tweeted before taking off on a 12-hour flight to South Africa this month: "Going to Africa. Hope I don't get AIDS. Just kidding. I'm white!" Despite having only 200 followers, the backlash to her thoughtless "joke" spread around the world before she landed - with the hash tag #HasJustineLandedYet trending while she was in the air. On arrival she deleted the tweet, then her Twitter account and entire online presence. Her employer said after the incident they had "parted ways" with Sacco.
Big game hunter
When American Melissa Bachman last month tweeted a photo of herself posing with a hunting rifle and a dead lion with the words: "Incredible day in South Africa...What a hunt", she was roundly condemned. Comedian Ricky Gervais retweeted her photo, adding: "Spot the typo".
Nokia NZ flips the bird
Nokia New Zealand tweeted a mysterious obscenity to its followers in November. The offending tweet was promptly deleted and was followed by this apology:
"Hi everyone, contrary to the last tweet,we love our Nokia NZ fans! Apologies to those who were offended - we're investigating the source now."
The company later said a hacker was the likely culprit.
The Edge radio DJ Dominic Harvey faced a swift response over a tweet posted while watching the auditions for The X-Factor NZ: "Girls rapping? Hardly ever a good idea". Kiwi rapper Coco Solid was among those angered by the comments and called for people on social media to let the radio station know Harvey's tweet was offensive.
Harvey was a slow learner, being caught in the crossfire again tweeting about The X-Factor NZ, this time by linking a contestant to a Once Were Warriors character who was the victim of rape: "Poor Gracie! First molested in her own bed by uncle bully. And now kicked out of #xfactornz." The tweet earned criticism from many - including Harvey's wife and fellow radio host Jay Jay Feeney.
Tweet security breach
In October, Minister of Police Anne Tolley surprised followers with a one word tweet, "poopoo". She later explained her account seemed to have been hacked and said someone was "playing silly buggers". Her message for the hacker: "I'm sure your parents will be very proud".
Boston marathon scones
In the wake of the Boston Marathon bombing, recipe website Epicurious made one of the worst attempts at "real-time marketing" by tweeting recipe suggestions for those in Boston and New England: "In honour of Boston and New England,may we suggest: wholegrain cranberry scones!"
Selling shoes through Syria
American clothing designer Kenneth Cole got himself in hot water a second time by trying to link footwear sales to the situation in Syria in September: "'Boots on the ground or not, let's not forget about sandals, pumps and loafters. #Footwear." He'd earlier fielded criticism for referencing the uprising in Egypt.
Election day lapse
Last month, Labour leader David Cunliffe overstepped Electoral Act rules when he tweeted on the day of the Christchurch East byelection: "If you are resident in Christchurch East don't forget to vote today - for Labour and Poto Williams". Statements published on polling day likely to influence electors are in breach of the Act. The post earned Cunliffe a written warning from police, and he acknowledging the mistake by donating $1000 to the Stepping Stone Foundation in Christchurch.
In February, Burger King and Jeep were hacked and temporarily lost control of their Twitter feeds. BK bore the brunt of the attack,when hackers changed its name and logo to"McDonalds" and tweeted about employees taking drugs and the company being sold to its golden-arched rival. It was a few hours before the company suspended its account.
A picture showing singer Robin Thicke at a party with his arm around an unidentified blonde was tweeted to his wife, Paula Patton, in August. The photo was taken in front of a mirror and shows Thicke's hand grabbing the woman's behind.
A casually racist tweet from American company Home Depot forced a grovelling apology and the subsequent dismissal of the employee who posted it. The offending picture had two African-American employees with a person in a gorilla mask between them, accompanied by the words, "Which drummer is not like the others?"
Words going wild
One thoughtless comment posted online can easily spiral out of control, a social media expert says.
"People don't quite understand how quickly things can snowball," said John Randels, partner of social media marketing company MOSH.
People often use Twitter as a "stream of consciousness" and don't realise how quickly things can spread on the internet - as was demonstrated by former PR executive Justine Sacco, who only had 200 followers, yet her "joke" tweet about AIDS in Africa made headlines around the world.
"Simply, if you wouldn't say it in a room full of strangers, don't tweet it," Randels said.
He advised companies to make sure they have governance or safeguards around what their employees can or can't say on company social media accounts.
Also helpful in avoiding a Twitter trip-up is keeping your password secure, and your smartphone out of reach when you're indulging in a few beverages.
But if for some reason you do make a social media faux pas, Randels suggested taking "a moment to figure out how to diffuse it", without letting emotions get the better of you.
Top Kiwi Tweeters
Kiwi music star Lorde has had a year to remember: a number one hit on the Billboard charts, four Grammy nominations- and topping the charts of Kiwi tweeters.
The teen songstress has surpassed all other names in the New Zealand Twitter scene this year to reach more than 700,000 followers.
She's eclipsed former top tweeter Sonny Bill Williams, who has more than 330,000 followers.
Rugby star Dan Carter is not far behind, with a respectable 289,000, and keeps his followers interested with regular rugby gear giveaways.
Also drawing a Twitter crowd is young social media sensation Jamie Curry, who earned her online fan base through her Jamie's World Facebook page, which has more than 6.5 million "likes".
And Filipino-Kiwi Kimpoy Feliciano, who describes himself on Twitter as "Superman. Single. 6'0. Filipino. Catholic. Dancer. Recording Artist", has gathered more than 500,000 followers, while still being unknown to most Kiwis.