The importance of social media training was highlighted by Labour MP Emily Thornberry tweeting a picture that many found condescending and classist. Many people tweet without thinking and those in a position of power routinely get themselves into trouble because of this. Reputation is everything in business and it can be destroyed with a single tweet. Twitter is a great resource but many forget how powerful it is and that tweets are not private. Clicking ‘tweet’ can ruin careers.

Thornberry’s infamous tweet featured the St George Cross flag, draped from a suburban home which had a white van parked in the driveway. The now ex-shadow attorney-general for Labour lost her job because of the tweet which not only damaged Thornberry, but also the Labour party as a whole. Ed Milliband was said to be ‘furious’. Communities Secretary Eric Pickles said: “We should have pride in flying the Cross of St George – don’t knock the national flag of England.”

Prime Minister David Cameron also said the Labour MP’s actions were “completely appalling” and made a suggestion that she was “sneering at people who work hard, are patriotic and love their country”.

After the incident Twitter founder Jack Dorsey was asked if the reaction to Emily Thornberry’s tweets made him frightened at the power of his creation. He said: “I don’t think it’s any different from what we’ve been doing as a humanity – it’s just faster.”

Other people who have lost their jobs because of inappropriate tweets include:

CNN Middle East editor Octavia Nasr wrote a controversial tweet regarding Lebanon’s deceased Grand Ayatollah Mohammad Hussein Fadlallah. Nasr wrote of her “respect” for Fadlallah, who was very anti-American and was also linked to bombings that killed more than 260 Americans. She later said she had been referring to Fadlallah’s “attitude” and apologised for trying to discuss a complex figure on Twitter.

Politician Stuart MacLennan was fired by the Labour Party after making a number of offensive tweets. He referred to Commons Speaker John Bercow as a “t**”, David Cameron a “t***” and Nick Clegg, the Liberal Democrat leader, “a b******”.” He also referred to elderly voters as “coffin dodgers”. He apologised for the tweets and was removed from the party’s ticket.

Former MLB pitcher Mike Bacsik lost his job as a radio producer after drunk tweeting racist comments during a Mavericks-Spurs game.

Comedian Catherine Deveny was fired from a job writing for Australian newspaper The Age when she tweeted about her hopes that Steve Irwin’s daughter gets laid.

Her former boss, editor Paul Ramadge, said, “We are appreciative of the columns Catherine has written for The Age over several years but the views she has expressed recently on Twitter are not in keeping with the standards we set at The Age.”

TV extra on Glee, Nicole Crowther, tweeted about some plot spoilers she had heard on set. A big no-no in the entertainment industry. She was then fired via Twitter by the show’s producer, Brad Falchuk, when he tweeted in response: “Hope you’re qualified to do something besides work in entertainment.”

Comedian Gilbert Gottfried was the voice of the Aflac duck and made jokes about the Japanese tsunami. “Japan is really advanced. They don’t go to the beach. The beach comes to them.” He tweeted. Unfortunately for him Aflac is the largest insurance company in Japan and he was fired.

A woman called Connor Riley got a job offer from Cisco and tweeted: “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.” Cisco employee Tim Levad then replied: “Who is the hiring manager? I’m sure they would love to know that you will hate the work. We here at Cisco are versed in the Web.” Oops.