Facebook’s growth is increasingly fuelled by users in emerging markets, including Latin America and the Middle East. But it still faces local competition in many countries.

It’s been a tough week for Facebook, with share prices falling sharply after its widely hyped IPO. But that doesn’t change the fact that the social networking giant now reaches roughly one in eight of the world’s population.

And it’s still growing fast internationally, especially in developing countries in Africa and Latin America.

According to a recent report by the International Telecommunications Union, social media use has now passed the billion-user mark. Of these, 900m have Facebook profiles. Its massive global following translates into big opportunities for social media marketers to connect with customers in emerging markets.

In the last year, Facebook has overtaken local competitors in many countries, including Brazil. It edged past Google’s Orkut earlier this year. It also overtook the home-grown Hyves in the Netherlands, which saw usage drop 38% in 2011. High-profile users and its “real name policy” helped drive up usage in Japan, where it’s outpaced Mixi, and now battles Twitter for the top spot.

More than half of Facebook’s revenue now comes from outside the United States. According to its own figures, it has achieved an impressive 85% market penetration in Chile, Venezuela and Turkey. This compares to just 60% in the USA and UK. And it’s growing fastest in Latin America and the Middle East, fuelled by growing, young, middle-class populations.

That’s not to say other networks aren’t giving Zuckerberg’s creation a run for his money. The world social media map is more diverse than it might appear at first glance. Twitter is the second most popular network in many countries, and is expected to grow four times as fast in the USA this year.

Both these two have still to overcome their ban in China under censorship laws. Instead, the socially-engaged Chinese online population turn to Qzone, Renren, and Sina Reibo, a micro-blogging site similar to Twitter. Youku is a local version of YouTube. Even if the ban is relaxed, it will still be difficult for newcomers to establish themselves in a crowded market.

In fact, Facebook’s performance in Eastern Asia has been disappointing so far. In South Korea, one of the most tech-savvy nations, users still overwhelmingly prefer Cyworld. This was one of the first networks to successfully make a profit by selling virtual goods. And in Japan, Mixi is managing to hold its own when the high number of mobile users are taken into account

Mobile use has clearly proved a headache for Facebook, since the company has still to make any “meaningful revenue” from its growing number of mobile users. This could prove more of a challenge as it begins to depend more on emerging markets for growth. In much of Africa, Asia and Latin America, a large proportion of web users are “mobile-only” and rarely, if ever, use computers.

One rapidly expanding market is India, as more of its vast population gets online. It’s predicted that there will soon be more Indian than American Facebook users. But most of them still rely on mobile connections to get connected, due to limited broadband coverage and the expense of laptop and desktop computers.

And even in Western countries, smaller “niche” networks are gathering market share. LinkedIn is building on its reputation as a site for business networking, while Xing plays a similar role in northern Europe. The two Russian giants, Vkontakte and Odnoklassniki, are both looking at extending their reach into Eastern Europe and have recently launched in more languages.

For marketers, Facebook and Twitter might be the top two, but this isn’t the case everywhere. The growing importance of China and Russia means it’s certainly worth paying attention to other key players.

With the total number of social networkers expected to reach 1.43 billion this year, it will be interesting to see the winners and losers. The social media map is still far from a homogenous one.

Image credit: Vincenzo Cosenza