Digital marketing agency VML is acquiring 10-year-old Chinese social media agency Teein, its second purchase in China in less than a year.

With the addition of Shanghai-based Teein, which has 170 employees, China will be the second-biggest location after the U.S. for Kansas City-based VML, which is part of WPP's Young & Rubicam. VML entered China less than a year ago, when it purchased Chinese digital agency IM2.0 in October 2013.

Global agencies have been in hot pursuit of independent digital and social shops in China, which has the world's biggest number of mobile phone subscribers and internet users, and where local know-how is especially crucial. China's government blocks access to most Western social media, including Facebook, Twitter and YouTube, and influential Chinese social networks have developed in their place.

Teein does social listening, marketing and CRM, for clients including Estee Lauder, Google, SAP and Danone. Teein's unaudited revenues were $7.1 million for the year ended Dec. 31, 2013, with gross assets of $2.2 million.

Teein has already worked with VML in China, for example on a "war room" for social media listening and response for Adidas around the World Cup.

"The best acquisitions and partnerships happen when you truly work together and deliver for a client together," said Jon Cook, VML's CEO. The company was also interested in a set of social media tools that Teein had developed.

One of them "tracks celebrity and key opinion leader sentiment and influence to see which voices are most influential in China," Mr. Cook said. "So as a marketer you can understand not only who has the most influence but get an excellent idea of who is being influenced, which helps make decisions with brands about who to align with and where to place messaging."

Teein's tools are China-specific, but Mr. Cook said the company would use some of the processes behind them to influence its global thinking.

Teein's CEO and founder Roy Yan will remain in place, reporting to Chris Tung, who founded VML IM2.0 and will continue to lead VML's operations in China. Of VML's 2,000-plus employees globally, about 420 are in China.

Mr. Yan said he is looking forward to gaining "innovations and technical skills from VML's global experience to improve our ability to serve our clients."

Teein opened for business in China in 2004, an eternity in social media terms. To put things in perspective, Facebook was founded the same year. The current most popular Chinese social networks – Weibo and WeChat – were launched in 2009 and 2011 respectively. Back in 2004, most of Teein's work centered on forums and bulletin board sites.