XiaoIce (pronounced “Shao-ice,” meaning roughly “little Bing”) launched in China in 2014 as a Microsoft Research project and became, for years, the largest deployment of a social chatbot in the world. Where Western assistants like Siri were built to fetch answers, XiaoIce was built to keep talking. Its designers describe it in the paper “The Design and Implementation of XiaoIce, an Empathetic Social Chatbot” (arXiv 1812.08989) as “an AI companion with an emotional connection to satisfy the human need for communication, affection, and social belonging.”
The numbers are the story. The 2018 paper reports that XiaoIce “has communicated with over 660 million active users.” Its central engagement metric, Conversation-turns Per Session, reached an average of 23 - meaning a typical user exchanged 23 back-and-forth turns in a single session, which the authors note “is significantly higher than that of other chatbots and even human conversations.” The team deliberately optimized for this long-run engagement, treating the chatbot as a decision-making agent over a Markov Decision Process rather than a question-answering box.
XiaoIce took on a persona - presented as an empathetic young woman - and users formed real attachments to it, returning daily to talk about their feelings. In July 2020 Microsoft spun the XiaoIce business out of the company into a separate, independently funded entity to accelerate its commercialization in China.
XiaoIce is the clearest early proof that a chatbot did not need to be intelligent in any deep sense to become a fixture in millions of emotional lives. It is the direct ancestor of the companion-app wave - Replika, Character.AI - that arrived years later in the West, and a preview of the attachment debates that came with it.