SO here is the list of the most popular social networks of the world:

1. Facebook - 1
2.Twitter- 8
3.Google PLUS - Dnt Know!
4.LinkedIn - 112
5. Tumblr - 32
6. Vkontakte - 38
7. Flickr - 131
8. deviantART -
9. Stumbleupon - 148
10. Myspace - 161

Source: http://rosyside.com/pt/List-Of-the-most-popular-social-networking-sites.6-10-2013/blog.htm

I assume the number beside them is their Alexa rank which is based on traffic. I think Google Plus has to take the number one spot because it uses a subdomain of google.com.

Hi all! Formerly known as Facebook, Meta is a technology giant that has had a profound impact on the way we communicate and consume information. Through a variety of social media platforms and digital services, Meta has become a central player in the digital space, dominating the market and influencing the way we interact with the world around us. Today, their platforms are used by billions of people around the world, and positive meta reviews indicate that users are happy to use their digital platforms.