Best Social Networks Have Crossed Millions of Active Users in 2013

1. Facebook: 1.06 billion monthly active users, 680 million mobile users
2. YouTube: 1 billion users
3. Twitter: 500 million total users, more than 200 million active users
4. Google+: 343 million active users
5. Shazam: 300 million users
6. Skype: 280 million users
7. LinkedIn: 200 million users
8. Soundcloud: 180 million monthly users
9. Pandora: 175 million registered users
10. Viber: 175 million users
11. Tumblr: 170 million users, 100 million blogs
12. SoundHound: 130 million users
13. Paypal: 117 million users
14. Dropbox: 100+ million users
15. Instagram: 100 million users
16. Ebay: 100 million active users
17. WhatsApp: 100 million users
18. Tango: 100 million users

And, a few well on their way:

Flickr: 87 million usersYelp: 78 million usersWordPress: 74 million blogsPinterest: 48.7 million usersReddit: 43 million users