Where are Facebook’s mobile-only users coming from? Probably not iPhones

Facebook revealed that 102 million users accessed Facebook solely through mobile devices in June, according to a document filed with the Securities and Exchange Commission.

However, the 23 percent increase since March doesn’t necessarily mean that users are ditching desktop in favor of their iPhone or Android device. Facebook is growing rapidly in mobile-first areas like India and Indonesia, which have large bases of feature phone users. This is often overlooked when people consider Facebook’s growth and opportunity in mobile because so far the company has not offered a breakdown in the demographics of its mobile users. However, based on trends in feature phone usage and stats Facebook has previously shared, much of the social network’s mobile-only usage seems to be coming from emerging markets, though time spent on desktop is likely decreasing in favor of mobile within the U.S. and other developed markets.

Worldwide, Facebook’s mobile monthly active users increased 67 percent from 325 million in June 2011 to 543 million in June of this year. The company noted that mobile usage is growing in all regions, and it highlighted the U.S., India and Brazil as key sources of this growth, but it did not say where the mobile-only users are coming from.

However, last month Facebook Head of Mobile Partnerships Emily White shared that 30 percent of new users in India are registering for the site via mobile phones. It’s likely these users are among those who never visit Facebook on desktop. The company says it had 59 million MAUs in India in June, an increase of 84 percent compared to the same period in 2011. An analysis using the Facebook ad tool suggests that about 30 percent of India’s users are active feature phone users and about 10 percent are Android or iPhone users.

Other emerging markets are also driving the social network’s mobile-only growth. White said that 90 percent of users in Africa use mobile phones. According to the document Facebook filed Tuesday, the social network also saw a 24 percent increase in Indonesian users since June 2011. An analysis using the Facebook ad tool suggests that about 36 percent of users in Indonesia are active feature phone users and about 5 percent use iPhones or Android devices. Like in Africa and India, Indonesia is a region where many people are accessing the Internet for the first time through their phones.

In the U.S., Canada, Europe and other desktop-first areas, users are accessing Facebook from both personal computers and mobile devices. Overall, 441 million mobile MAUs accessed Facebook from both platforms in June. CEO Mark Zuckerberg said last week that mobile-connected users are more active than desktop-only users. Specifically, mobile users are 20 percent more likely to use the service on any given day. However, even though these users are still accessing Facebook on desktop, the amount of time they spend on mobile is certainly increasing. The social network experienced a 2 percent decrease in the number of ads delivered in the U.S., despite 10 percent growth in daily users and upping the number of ads per page. CFO David Ebersman attributed this decline to increasing mobile usage and said the company is seeing similar trends in other developed markets.

Facebook reported that 58 million users were mobile-only in December 2011, and 83 million were mobile only in March 2012. The 102 million mobile-only users Facebook reported for June make up little over 10 percent of the social network’s total 955 million monthly active users. In December 2011, 13 percent of total users at the time were mobile-only.