Yao Fang, marketing director of Royal Caribbean China, a unit of Royal Caribbean, the Norwegian-American global cruise company based in Miami, says that unlike traditional marketing channels, weibo comes at a lower cost, and serves as a supplementary marketing channel. She says that though it is difficult to quantify exact contributions, there is no doubting the boost it gives to overall turnover.

"Micro blog marketing is the next big thing, as Sina has become a stable platform, with a daily growth in user numbers and viscosity. It is a huge marketing opportunity," she says.

Silloway says that though Starbucks has stores in 16 different provinces, it is difficult to establish a pan-China presence as TV marketing is an expensive affair.

"Micro blog is market-efficient, low-cost and interactive, and also gives us instant feedback on what the general perception is," she says.

According to statistics from eMarketer, a US digital market research firm, social network advertising spending in Asia-Pacific will grow by 48 percent from $1.38 billion in 2012 to around $2.5 billion this year. In the US, it is expected to reach $4.1 billion this year and $5 billion in 2014.

For China, the figures are higher. As the biggest SNS market, the advertisement spending on social media will experience a fast increase of 51.3 percent, reaching $612 million this year, it says.

Chu adds that when it comes to fifth and sixth-tier cities in China, where roadside boards are rare, micro blogs are probably the best or sometimes the only channel to reach people.

Though micro blogs are immensely popular in China, they have also received much flak for their similarity with global SNS platforms like Twitter. Both the websites sport distinctive layouts with similar features for posts, referrals and comments. But micro blog differs from its Western peers in terms of the added features it provides.

Jeremy Webb, a digital strategist from Ogilvy, says that the real difference between the two platforms lies in the low penetration rate of the US-based platform.

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Twitter still has a relatively low penetration rate in the US market. Of the 74 percent of American adults who use the Internet, only 8 percent use Twitter, says a recent study by Pew Research Center, an American think tank. In contrast, the percentage of micro-bloggers among total netizens in China has grown by 6 percentage points to 54.7 percent.

From a company perspective, the added features of Chinese micro blogs make them ideal for online marketing campaigns.

On Sina Weibo users can watch videos and see pictures seamlessly. But on platforms like Twitter video and pictures are often in the form of a hyperlink that has to be clicked to access the content.

"Platforms like Twitter have a limitation of 140 letters for one piece of information, whereas Sina Weibo allows 140 characters and various other features like pictures, videos, and hyperlinks. This helps create more vivid marketing campaigns for companies," says Gao Xiang, communications manager of Nokia China.

Apart from the better return on investment, customer retention is another factor that attracts foreign companies to micro blogs.

Companies like Royal Caribbean regard a micro blog as a window for customer services, or a channel for product promotion, and also an option for delivering after-sales services.

"What we value most about micro blog marketing is the increase in user viscosity," says Yao. "Activities on the micro blog will increase interaction with consumers and help increase the influence of our campaign."

The company started its official Sina Weibo account in 2011, and has around 130,000 followers. They also produce four to five interesting topics daily and communicate with followers. The team also initiates marketing campaigns, such as promotion information and vouchers to transfer online traffic to offline sales.

Yao says that on average, about 2,000 to 3,000 of their followers participate in campaigns. Last year, about 110,000 passengers boarded the company's cruises in China, triple the total number in 2011. This year, the company plans to launch more campaigns, she says.

When it comes to a public relations crisis, official micro blog accounts can be quite effective during the feedback and management process.

According to a white paper prepared by Ogilvy called Crisis Management in the Micro blog Era, nearly three major PR crises of last year had their roots in micro blogs, including companies such as KFC and McDonald's.