This paper first constructs a numerical text review score by applying text analytics and machine learning techniques to more than three million online text reviews collected from the Airbnb platform. Next, we employ the text review score to analyze the effect of review length on text review score and obtain insights on the interplay between the text review length and online reputation. The main contributions of this paper include: experimenting with advanced text analytics and machine learning approaches to assess online reputation; constructing an innovative text review score as a new online reputation measure; building a large knowledge-based review corpus with labels; and obtaining important insights about the effects of text review length on online reputation. Further, it has managerial and business implications for all internet platform markets and the sharing economy players seeking to build more effective online reputation systems.