By some measures, Twitter is the number three social network behind Facebook (1.5 billion) and Facebook-owned Instagram (400 million). Using a broader definition of social platforms, it is also dwarfed by Google-owned video sharing service YouTube with one billion users; other messaging platforms with a large user base include WhatsApp (900 million), China-based QQ (860 million), Facebook Messenger (800 million) and Chinese app WeChat (650 million), according to the website Statista.
China's blogging platform QZone has an estimated 653 million users and Yahoo-owned Tumblr 555 million, according to Statista. Google+ claims more than 400 million users but the platform is seen as having far less engagement than rivals.
LinkedIn, the professional social network, has some 414 million registered members, and the bulletin-board style network Pinterest has 100 million. Snapchat, known for its disappearing messages and its appeal to young audiences, is seen as a rising threat in the sector, claiming 100 million users daily and a growing list of media partnerships.