Microsoft's chatbot Xiaoice has now over 660 million active users. The chatbot has more than just users. Xiaoice also has over 5 million followers on Weibo (the Chinese Twitter), making it more than a tool; the AI personality has a fan group and reached celebrity status in China.
Xiaoice is more than a simple chatbot; it's an empathetic social bot which makes the user the main topic of the discussion, unlike other humans the AI has unlimited patience and is thus very good at making people feel understood and valued.
Xiaoice has features like Alexa, Siri, and Google Assitant, basically Microsoft Cortana's capabilities, but it also ads the empathetic factor.