Twitter, which allows users to publish 'tweets' of up to 140 characters, is best known as a platform for celebrities to speak directly to the public, and vice versa.
It can make Twitter look daunting for smaller businesses, but if used with a little thought, it is arguably the easiest social media service to exploit with limited time and expertise.
As messages have to be short, they can be written quickly – although they should always be written with care – and the fact that users publicly follow others allows businesses to know who their potential customers are.
Twitter can be used like selling from a market stall to an interested crowd, with the rest of the world passing by.
Rather like market traders, experienced business tweeters inject some personality into tweets; respond to questions and comments (directed by using @ then the target account's name); and use visual aids, in Twitter's case by attaching pictures.
A bit of banter goes a long way, although should be used with care – people have faced severe legal consequences over tweets. Tweets can be deleted, but may have already been read and copied by the time you do this; best not to say anything stupid in the first place.
Some businesses have made Twitter a key part of their marketing. One is BrewDog, a craft brewer and bar owner based in Ellon in Aberdeenshire. Its 'master gunner' Sarah Warman – more conventionally, she handles digital marketing and events – spends a couple of hours a day on Twitter. She has backup from other staff when she's ill or on holiday, but says she tends to monitor Twitter most of the time: "I'm never off the clock, really."
"You can't provide someone with a taster of beer on the internet," says Warman, so instead she focuses on telling the account's 25,000 followers what the firm is doing, whether that involves new beers, new stock or other news. She also uses it to answer tweets from followers (those including @brewdog).
"As far as possible, we try to answer every question," she says. If things are quiet, she will also respond to those simply mentioning the firm in a tweet as well.
Followers appear particularly interested in how the beers are made.
"They ask a lot of questions about the equipment, what things are for, the science behind it," Warman says. She encourages this through using pictures: "We post an image from the brewery every day."
One option with Twitter is to monitor popular hashtags, codes helping users to search for tweets of interest, and use them in marketing tweets; but Warman prefers to use her own. On Friday afternoons she looks for those using the hashtag #deskbrew, for those having a beer in the office. While it isn't possible to keep this for BrewDog's use, it has become associated with the firm.
BrewDog runs 10 bars, with more in the pipeline, and each has its own Twitter account – such as Glasgow's with 2,400 followers. These are monitored by someone working in the bar, whenever it is open, with the idea of it being equivalent to talking to bar staff (although without being able to order a drink).
"If they get a question about what's in store, they can have a look and answer those questions immediately," says Warman.
The firm opens an account for a new bar before it opens, to allow a following to build. Warman also asks where followers would like to see new bars open, and pays £1,000 bounty for any suggestions that led to an opening.
She compiles a monthly report based on feedback she receives from social media channels on trends and themes. "If people are looking for a specific style of beer, and we can tell there's a market for it, it's worth us trying that," she says.
The firm also uses Google Analytics to track sales from its online shop that result from tweets, although it's harder to do this for the bars.
Overall, she advises anyone using Twitter to ensure that everything they tweet is "relevant, entertaining and informative – those are things that will make it viral content, worth sharing".
Patrick Neale is co-owner of a smaller business: Jaffe and Neale Bookshop in Chipping Norton, Oxfordshire. He reckons he spends "not enough, five or ten minutes a day" on the shop's account.
It is in his own name: "For a small business, your personality is part of the business," he says. "It gives a warm feeling."
Neale uses his account partly to stay in touch with authors and publicists. It is much easier than writing an email, and can make a writer more amenable to attending an event.
"Not a lot of energy has been expended," he says.
Neale, also president of the Booksellers' Association, says some booksellers use Twitter to drum up customers by offering a discount to the next five people who walk in if things are quiet. He prefers to use the account to build the shop's brand, such as by tweeting pictures of events.
"Even if people don't come to the events, they love to know we're doing them," he says. "It shows we're a vibrant and energetic place."
He adds that, even if someone uses an account mainly to talk to business contacts, it's important to remember that customers are always able to read tweets. He recalls being reprimanded over a slightly risqué tweet about a parody of adult fiction using the hashtag #50ShedsofGrey.
The shop occasionally gets customer service queries through Twitter, although mostly about events and the shop's café rather than books. The account's background design includes all its contact details, as well as the various goods and services it offers, in the form of Penguin book spines – another way of spreading its message.
Neale says he has concerns over social media – "I have a fundamental concern that it is eating into the amount of time people are reading books" – but thinks a small business can use Twitter without spending too much time.
"It's allowed me to completely ignore Facebook," he says.