When Skyler Wiet signed up for Sina Weibo, the Chinese micro-blogging service, several months ago, he had more than one reason.

"My broader interest in China and social media both played a role," he said.

"Hello China. Let's get to know each other better."

That was the first message on Weibo from the New York-based public policy adviser, and it best explains why an increasing number of foreigners are using Weibo.

For Wiet, who is studying Mandarin, joining conversations on Chinese social media channels makes him better engaged with Chinese people.

"It's exciting, especially when they understand my Chinese. It can be equally eye-opening to see how Chinese people are reacting to an international event and to discover that China has someone like Feng Jie (a blogger who has 1.4 million followers on Weibo), who isn't so different from Internet celebrities and reality stars that have emerged in other parts of the world," said Wiet.

According to Sina Weibo, it now has about 450,000 users in the United States out of its total of 250 million as of late November. There is no official record of the nationality of the US users. They could be US citizens, Chinese students or people from other countries.

China's total Internet users hit 450 million early this year - larger than the whole US population - and that number is expected to grow.

Kenneth Wisnefski, founder and CEO of WebiMax, a US-based search engine optimization firm, said Sina Weibo is following the same development pattern as Twitter, which took about two years to be fully accepted before it became the dominant social media platform it is today.

One phenomenon that is getting obvious is that more and more globally recognized figures, including billionaire philanthropist Bill Gates, International Monetary Fund chief Christine Lagarde and actor Tom Cruise, are becoming Weibo users.

Weibo's overseas users mostly utilize the service to reach Chinese audiences. And for celebrities, their reason is quite simple: to promote themselves or their program in China.

Gates is a popular Sina Weibo user, currently with 2.19 million followers.

Lagarde made her Weibo debut in early November, posting her first message which reads: "Hello Sina Weibo, looking forward to sharing updates here. Christine Lagarde, Managing Director, IMF."

By the end of the day, Lagarde's account had drawn about 40,000 followers and had more than 1,000 comments. She currently commands 150,000 followers.

The site also helped politicians like San Francisco Mayor Ed Lee, a Chinese-American, to reach Chinese audiences during the recent mayoral elections.

During election day in November, Lee posted messages calling for support. Later that day the first elected Chinese-American mayor posted to his followers on the site: "Thank you San Francisco!"

Wiet, who is working on some research projects on Chinese social media platforms, said it is "a smart investment and a powerful tool to understanding what a huge portion of the global population is thinking".

"On top of all of that, I think anyone who starts getting engaged on Chinese social media channels will find out pretty quickly how interesting it can be," Wiet said.