“Twitter is a free social networking and microblogging service that enables its users to send and read others’ updates, known as ‘tweets’. Tweets are text-based posts of up to 140 characters displayed on the author’s profile page and delivered to followers who have subscribed to them.”

Chances are you knew that already. But you might not have done nearly five years ago, when these words introduced Twitter in the World Economic Forum’s Technology Pioneers 2010 report. Since then, the number of active users on Twitter has grown almost tenfold, from 30 million to 271.

By the time it was named as a Tech Pioneer, Twitter had demonstrated its capacity to break news, notably with the ditching of a United Airlines plane in the Hudson River in January 2009: photos were being shared on Twitter well before traditional news outlets were covering the story. Recognising the value of real-time information, later that year both Google and Bing signed deals with Twitter to include tweets in web searches.

But while Twitter might have been “changing the way individuals and companies share and get their information”, as the Forum report put it, there was still a good deal of uncertainty around its future direction, not least its business model. In 2009, co-founder Biz Stone blogged that the company had “just begun exploring” commercial opportunities.

Twitter was also dividing opinion in the media community. A 2009 article in the American Journalism Review was still able to wonder: “Does it ‘work’ in any meaningful way — as a news-dissemination channel, a reporting and source-building tool, a promotional platform? Or is it merely, to buy the caricature, just a banal, narcissistic and often addictive time suck?”

Now an order of magnitude bigger, Twitter’s place in both the media and business landscapes is firmly established. Nor is there much remaining doubt about its ability to generate revenues: in the second quarter of 2014 it brought in $312 million, mostly from selling the ability to promote tweets, trends and accounts.

Yet arguably more noteworthy than Twitter’s journey towards profitability since becoming a Tech Pioneer has been its expanding social impact. Twitter was widely credited with facilitating the pro-democracy 2011 Arab Spring uprisings and more recent protests in countries such as Ukraine and Turkey, where the government briefly banned the service altogether.

Freedom of speech on Twitter is increasingly a legal battleground, as described by Bahrain human rights activist Esra’a El Shafei recently on the Forum Blog. There are cases of Twitter users being imprisoned for their tweets, and Twitter’s approach towards censorship is the focus of growing attention: since 2012, it has had a policy of allowing national authorities to censor tweets within their country, while keeping the content visible in other jurisdictions.

More broadly, Twitter’s deeper penetration into the mainstream is arguably changing the way we communicate – along with video-sharing service Vine, bought by Twitter in 2012, with its six-second limit emulating the 140-character limit on tweets. Linda Abraham, co-founder of comScore and chair of the World Economic Forum’s Global Agenda Council on Social Media, argues on the Forum Blog that individuals, media outlets and corporations alike still have more work to do in getting to grips with how best to handle this “compression of expression”.

Twitter’s expansion shows no signs of slowing: it is now available in 35 languages, 77% of its accounts are outside the US, and 78% of users access the service via mobile, the primary means of internet access in the emerging world. Co-founder Jack Dorsey believes that within ten years, it has the potential to “reach every single person on the planet”.

Author: Andrew Wright is a writer working for the World Economic Forum. The 2015 list of Technology Pioneers will be announced on Tuesday, 26 August. The 2015 list of Technology Pioneers will be announced on Tuesday, 26 August.

Image: Men are silhouetted against a video screen with a Twitter logo. REUTERS/Dado Ruvic