Facebook Inc (NASDAQ:FB)’s user growth is slowing in North America, though it continues to grow by leaps and bounds in emerging markets. For example, the number of active Facebook users has grown from 8 million in 2010 to more than 100 million by the end of 2013. India is now the social networking giant’s second largest market. Facebook has also seen immense growth in other Asian countries and South America.

Facebook video ads

Facebook COO in India to meet with partners

So, the Menlo Park-based company is trying to extract more revenue from markets like India, Brazil and Indonesia. Facebook COO Sheryl Sandberg is in India this week to meet with advertising and business partners. Facebook is rolling out new, tailored ad formats in these countries in an attempt to boost revenues, reports The Wall Street Journal.

For example, the social networking company is testing a new ad in India that appeals to the popular “missed call” behavior in the country. People in India sometimes make a phone call and hang up before connecting to send a signal to their family members, “call me back.” Now Facebook is allowing mobile users to give a missed call to a brand advertiser by tapping an ad or clicking on a button.

Users then receive an automated return call from the brand that includes pre-recorded audio messages about things like cricket scores, shopping discounts, along with ad messages from the brand. It minimizes data charges for the user. The Mark Zuckerberg-led company has optimized these ads to work on slow wireless connections in emerging countries. The company is also improving its tools in such markets to help advertisers better target different user groups.

Facebook capitalizing on marketers’ growing interest in emerging countries

Facebook Inc (NASDAQ:FB) is trying to capitalize on advertisers’ growing interest in emerging markets. According to ZenithOptimedia, ad spending in Latin America will increase 12.5% this year, and 10.9% in “fast-track Asia,” which includes China, India and Indonesia. In contrast, ad spending in the U.S. is expected to grow 4.7%.

Facebook Inc (NASDAQ:FB) shares inched up 0.34% to $68.29 in early trading sessions Wednesday.