The No. 1 social network by country isn’t always Facebook, but it’s pretty close.

Social media statistics blog Vincos gathered data on the most popular social-networking sites by country, according to traffic data from Alexa, a subsidiary of Amazon.com that ranks websites and provides public commercial web traffic data. Facebook is the biggest social network in the world, taking the top spot in 129 out of 137 countries analyzed.

While Facebook FB, -0.93% is the most widely used social network in most countries, it’s not the biggest in every country, including China and Russia.

Facebook is blocked in China. Instead, virtual social butterflies in China use QZone as their social network of choice. The site is also blocked in Iran, where instead social networkers use Facenama.

In Russian territories, Facebook isn’t blocked, but social network users prefer the sites V Kontakte and Odnoklassniki, both traditional social networks with personal profiles and photo sharing options.

But the second-most popular social network tells a different story. In the U.S., people love Instagram, while Canadians prefer Reddit. Twitter TWTR, -0.05% has a strong presence in Europe.

Compare that to a map of most popular social networks from 2009, when Facebook hadn’t yet held its initial public offering, and when competitors for top social network in some countries still included Zing, Mixi and Friendster.

Many of those competitors no longer exist today, including Orkut, a site operated by Google GOOG, -3.23% that closed in 2014, and Friendster, which shut down in 2015.

Related:Is Instagram driving Facebook’s rapid growth?

Of course, Facebook may be No. 1 by a large margin today, but there’s a reason everyone hangs on its monthly active-user numbers at every earnings call. Flagging growth there might indicate users -- particularly younger users -- are beginning to take their networking elsewhere.

So what’s the fastest-growing social network? Recent data appear to point to Pinterest and Tumblr, according to GlobalWebIndex.

But the definition of what constitutes a social platform is shifting. Messaging apps, like WhatsApp, Snapchat and Facebook’s own Messenger, are proving popular alternatives to public platforms like Facebook and Twitter.

Among messaging services, the fastest-growing platform isn’t what you might expect (i.e., Snapchat) -- it’s Japanese app Line, though Facebook Messenger is showing strong growth.