By ELIZABETH HOLMES

Who would have thought typing such short messages could be so tricky?

By now, even the stodgiest companies have found their way onto Twitter. They have discovered it isn’t just another marketing channel with a funny name, it’s more like a conversation they need to join or risk losing influence over how consumers view them or their brands.

The service, which lets users send 140-character texts, or “tweets,” to people who have signed up to follow them, has proved to be an effective way to reach younger consumers and to help build a brand.

But there’s a flip side. The nearly six-year-old medium has become a very public complaint line, and ill-considered tweets or hacked Twitter accounts have caused plenty of embarrassment.

In March Chrysler Group LLP cut ties with an agency that handled its Twitter account after the agency sent a tweet that read: “I find it ironic that Detroit is known as the #motorcity and yet no one here knows how to f— drive.”

Kenneth Cole Productions Inc. apologized after making a joke on its Twitter page suggesting the Egyptian protesters who toppled the country’s government earlier this year were really clamoring for the company’s fashions. “Millions are in uproar in #Cairo. Rumor is they heard our new spring collection is now available online” the tweet read.

An April tweet on American Express Co.’s account that urged support of Planned Parenthood was sent after the account was compromised, the company said.

In the age of Twitter, companies have to engage with their customers on the public social platform. But there are some high-profile ways things can go wrong, Elizabeth Holmes reports on The News Hub. Photo: Getty Images.

This week AMR Corp.’s American Airlines found itself caught in a public spat after actor Alec Baldwin vented on Twitter after being removed from an American flight. “Flight attendant on American reamed me out 4 playing WORDS W FRIENDS,” Mr. Baldwin tweeted, referring to a Scrabble-like online game.

American replied via Twitter asking for his contact information. A day later, American tweeted, “UPDATE: Facts about yesterday’s removed passenger” along with a link to a statement giving a less-flattering account of the passenger’s behavior without mentioning Mr. Baldwin’s name. Mr. Baldwin deactivated his Twitter account after the incident and apologized to his fellow passengers.

Companies are adopting a variety of strategies for navigating Twitter’s pitfalls. One of the biggest issues is how many people to trust with a company’s account, known as its handle. Spread the authority too thin, and the burden can be overwhelming. Authorize too many people, and the risk of mishaps multiplies. Here’s how three very different companies—Southwest Airlines Co., Whole Foods Market Inc. and Best Buy Co.—are approaching the task:

Southwest Airlines

About 10 people have a hand in Southwest’s Twitter account, fielding questions about lost baggage, delayed flights and misplaced drink coupons.

Southwest started its account, @SouthwestAir, in 2007, initially placing it under the advertising division, but later moving it the public-relations department, where it was handled by social-media specialist Christi McNeill.

Ms. McNeill soon found she lacked the knowledge to answer some tweeted questions, such as the ticket counter’s opening time at a specific airport, or the authority to quickly resolve other matters, such as refund requests.

“I was a traffic cop of information,” Ms. McNeill said. “Can you imagine if you called into an airline and the person who answered the phone had to ask someone else for the answer?”

This year the airline’s communications department teamed up with its customer-relations team to recruit and train employees to answer questions on Twitter. At least one person from each unit monitors the account from about 5 a.m. to 11 p.m. central time, roughly matching Southwest’s flight schedule. The team is on call in the event of bad weather or service disruptions.

If someone tweets a complaint to @SouthwestAir, the reply may come from Whitney Bartels, via her account @SouthwestWhit. “So sorry to hear about your [lost] luggage. Have you filed a claim? Any progress yet?” she recently tweeted to an upset customer.

Southwest’s Twitter feed reflects its casual culture. That temporarily changed in April, when the fuselage on a Southwest plane ruptured in midflight. The carrier’s earlier tweets joking bout April Fool’s Day, quickly gave way to serious statements about the incident and Web links on how to rebook flights.

Using a modified version of the company’s social-media crisis plan, which covers how best to communicate and what to say in the event of an emergency, Ms. McNeill says, “We shifted our tone to be a little bit more corporate.”

“Enjoy the wifi!” Ms. McNeill tweeted to a customer before the incident. Shortly afterward, she got more serious, tweeting, “Southwest Airlines responds to loss of pressurization event on flight from PHX to SMF,” with a link to a Southwest statement about the event. She continued to provide updates.

Whole Foods

The upscale grocer has put its Twitter account, @WholeFoods, in the hands of a single employee, Michael Bepko, its global online community manager. Mr. Bepko says he spends about a third of his day on Twitter, monitoring mentions of Whole Foods, tackling shoppers’ questions and posting recipes.

“They’re easy, they’re delicious…serve a roast with the most!” he tweeted recently along with a link to a recipe for Italian pot roast.

Whole Foods launched its Twitter account in June 2008 and now has more than 2.1 million followers. Mr. Bepko, who took the reins about a year ago, says his goal is broader engagement with customers. Many of the chain’s stores now have separate accounts to answer local questions. In November, Whole Foods began a weekly Twitter chat, for an hour every Thursday, to discuss topics such as holiday menu planning, with its followers.

Mr. Bepko says he spends about 90% of his time talking to individual shoppers. Most of their inquiries are basic, such as when a Whole Foods will come to their neighborhood. Others, he says, require more research. Occasionally a customer will make an unusual complaint, about a dog outside a store, for example, or a bug in a bag of salad.

“Sorry to hear about this. Did you mention it to the store where the salad was purchased?” he replied to the bug complaint.

Mr. Bepko checks the company’s Twitter feed many times a day. “The online community doesn’t recognize office hours—nor should they,” he says. If a questioner has a request on Friday evening, “waiting until Monday is just not good enough.”

Best Buy

The electronics retailer has employed an army of associates to handle its various Twitter feeds. The main account, @BestBuy, sends its own tweets but also incorporates some from its more-specialized handles, such as @BestBuy_Deals, @GeekSquad and @BBYNews.

The Twitter arm of Best Buy’s help desk, which publishes under the handle @Twelpforce, exemplifies the company’s more-is-more approach to the medium. Tweets to the desk are answered by one of the roughly 3,000 Best Buy employees who have signed up for the task since the handle was launched two years ago, according to Gina Debogovich, who oversees U.S. social-media activity for Best Buy.

Having a range of workers participate lets the company tap many areas of expertise, Ms. Debogovich says. Questions tend to be about items a customer is interested in purchasing. “There is no right answer often,” she says.

To be part of @Twelpforce and other social-media outlets, Best Buy requires employees to enroll via a website that verifies their employment status and lays out terms and conditions. The company uses an internal video and its publicly available social-media policy, which prohibits such things as sharing nonpublic financial data and customers’ personal information, to explain what it calls its healthy usage guidelines to the @Twelpforce participants.

“Remember, your responsibility to Best Buy doesn’t end when you are off the clock,” the policy says.

Best Buy’s chief executive, Brian Dunn, tweets from his own handle, @BBYCEO. His musings range from sports topics to support for veterans. Sometimes customers use his account for complaints.

A customer recently tweeted Mr. Dunn to complain about the customer service at Store #310. He replied the same day with his personal email address and a request that the tweeter send him contact information. “We will be in touch. I want us to make it better,” he tweeted.

Write to Elizabeth Holmes at elizabeth.holmes@wsj.com

By RUSSELL ADAMS

News Corp. is in serious talks to hire former Bloomberg LP chief executive Lex Fenwick to be the new chief of Wall Street Journal publisher Dow Jones & Co., according to people familiar with the matter.

The hire, while not final, would fill a position vacated six months ago when the previous CEO, Les Hinton, stepped down amid the phone-hacking scandal at News Corp.’s UK newspaper division. When he resigned, Mr. Hinton, who ran the division before he joined Dow Jones, said that he was “ignorant of what apparently happened” at one of the company’s tabloid newspapers earlier, but characterized his lack of knowledge as “irrelevant” and said it was “proper” for him to step down.

Mr. Fenwick has spent 25 years at Bloomberg where he managed the financial-data giant’s operations in Europe, the Middle East and Africa before he was appointed CEO in 2001. He stepped down from that job in 2008, and since then Mr. Fenwick has been running Bloomberg Ventures, a wholly owned subsidiary tasked with developing new businesses.

A spokeswoman for Bloomberg had no immediate comment. Earlier this week Mr. Fenwick denied that he was joining Dow Jones, saying “I work at Bloomberg.” He couldn’t be reached late Friday.