When Canada's ambassador to China posted photos of his car on the embassy's Twitter-like weibo page, the instant, mass response boosted his country's image in a way that surely stunned many diplomats.

Hundreds of Chinese netizens posted comments marvelling that the Canadian envoy at the time -- David Mulroney -- was driving a relatively inexpensive car compared to the luxury vehicles favoured by their own officials.

In just one click, Ottawa had managed to engage a wide audience in a debate about corruption and transparency, using one of China's hugely popular social networks.

"Digital tools -- including social media -- are being used by an increasing number of countries," said Antonio Deruda, author of "Diplomazia Digitale", a book on the topic.

"It is an important process that can be very useful for administrations... Through social media, the goal is to establish a dialogue with the foreign public."

Dubbed "21st century statecraft" by the United States, the use of digital tools to help achieve diplomatic goals is on the rise in a world where the web has changed how people engage with each other and higher authorities.

Washington is at the forefront of this trend -- led by Secretary of State Hillary Clinton, who was made painfully aware of the power of social media when she lost the Democratic nomination to a tech-savvy Barack Obama in 2008.

There are now around 300 State Department-affiliated Twitter accounts globally -- which include those run by ambassadors or embassies -- over 400 Facebook pages and 180 YouTube channels.

US ambassador to Syria Robert Ford, for instance, has used the embassy's Facebook page to post declassified satellite images showing troop movements in civilian locations, in a propaganda tug of war with the Damascus regime.

The State Department has also organised Google+ Hangouts -- group video chats -- to engage with people in Iran on issues such as sanctions and studying in the United States.

"One of the benefits of using these technologies is we're in places where we don't have a diplomatic presence on the ground," said Victoria Esser, Deputy Assistant Secretary for Digital Strategy at the State Department.

-- 'It's indispensable to engage with the world' --

Other countries have also got in on the act in a bid to improve their political clout, or attract foreign investment and tourists.

Widely regarded as a symbol of the modern Arab woman, for instance, Queen Rania is a key asset in Jordan's soft power push. With Twitter, she is an even more powerful force, with each post reaching over 2.3 million global followers.

"Queen Rania is followed not only by people interested in Middle East issues and political issues, but by people who are more interested in what she buys in shops or where she goes abroad," said Deruda.

"This is a key point for digital diplomacy -- the importance of reaching a broader audience, not just the same old people who usually follow foreign affairs."

As such, top diplomats are increasingly holding live, virtual chats on social networks to engage with people whom they would otherwise never meet.

British foreign secretary William Hague took this a step further earlier this month, meeting five of his 109,000 Twitter followers to discuss Somalia, Europe and other issues in an effort to bring online interaction offline.

But for all its immediacy and accessibility, social media is a minefield where a misplaced comment can generate a whirlwind of controversy as fast as it takes to type 140 characters -- the length limit for tweets.

Linda Sobeh Ali, the Palestinian representative to Canada, was recalled in October 2011 after she retweeted a video of a Palestinian girl reciting a poem that begins innocently enough, but later mentions "destroying Zionism".

Social networks have also been used as platforms for public fighting matches.

In May, US ambassador to Russia Michael McFaul was severely rebuked on Twitter by Moscow about a speech he made on US-Russia ties.

Netizens watched with amusement as the Russian foreign ministry fired off nine consecutive tweets blasting McFaul, who was eventually forced to post a link to a blog post clarifying the message he had intended to get across.

Giuseppe Manzo, spokesman for Italy's social media-savvy foreign ministry, acknowledged the risks involved.

"The outreach you achieve with social media is much greater -- and thus the risks -- but we're still going through an adaptation process," he said.

"I believe it's indispensable to engage with the world out there... Why not exploit tools like social media networks to help us? That said, I believe traditional diplomacy remains key."

But Deruda said it was also crucial for governments to act on this engagement.

"If you start a conversation and I tell you what I think about your policies, or about your image, your leaders... and then I see you don't change anything, the dialogue is doomed to end," he said.

"This is a key point for the future of digital diplomacy."