Facebook has conquered western Europe, Australia and the US, but it is not king of the castle everywhere.
A study from Pingdom looked at 130 countries to find where Facebook is not in the top five most visited websites – from sixth place downwards there is normally a sharp drop-off.
Facebook is blocked in China – so that's one market of 420 million internet users it cannot access.
It is also weak in several other countries with their own take on social networking. It has a weak position in Japan and is less popular in eastern Europe and Russia than in countries like France and Germany.
Iran is another market with limited interest in Facebook – the site is 26th most visited in the country. Belarus ranks Facebook 11th, and Russia puts it in 10th place.
vKontakte, which looks fairly facebook-esque, is Russia's favourite networking site, while Orkut is still big Brazil, where Facebook ranks in eighth place.
But when Facebook wins it really does win – it typically claims at least 50 per cent of internet users in countries where it is in the top five sites.
The missing pieces of the jigsaw equate to 765 million users – half of that number would give the site another 382 million members. ®