- Facebook (monthly active users 2.2 billion - Alexa Rank #3)
- YouTube (1.6 billion - Alexa #2)
- WeChat/Weixin (1.1 billion - #2,537)
- Instagram (900 million - #17)
- Tencent QQ (803 million - #6)
- QZone (548 million) - #209
- TikTok (500 million - #3,204)
- Sina Weibo (446 million - #18)
- Tumbler (350 million - #65)
- Reddit (340 million - #13)
- Twitter (335 million - #11)
- Baidu Tieba (300 million)
- Snapchat (291 million - #4,480)
- LinkedIn (270 million - #30)
- Pinterest (230 million - #77)
- VK (120 million - #14)
- Huya (100 million - #565)
- YY (95 million - #270)
- Taringa (75 million - #811)
- Renren (? - #1,824)
- Nextdoor (? - #1,310)
Alexa rank doesn't track smart phone app use (Alexa tracks website use, and far from perfectly but it does provide some insight into how much use popular sites get). Most of the social media sites have most use via apps but many also have useful web sites. Some have much more of a bias to smartphone apps (WeChat for example).
Related: What I Would Include in a Redesigned Twitter Profile - Don't Lock Your Content Inside a Proprietary System