Why do some innovations in policy or practice take off, while others fizzle out? Social scientists and policy experts have grappled with this question for decades, studying the diffusion of new ideas and examining how and why states, organizations, and institutions adopt innovations to their policies or practices. In recent years, states have begun adopting innovations in data use and application, including accessing new data sources, combining data sets, and using different analytic methods. These efforts are designed to help states provide more comprehensive answers to policy and practice questions and to better inform their work. This brief examines the diffusion of a data innovation from 2014 to 2019: the introduction of the Multistate Longitudinal Data Exchange (MLDE), a collaborative system both within and between state data agencies. It is based on research and evaluation activities conducted over the past five years by Rutgers' Education & Employment Research Center (EERC) including data collected from over 40 interviews with state leaders and Western Interstate Commission for Higher Education (WICHE) representatives, observations of user group meetings, surveys, and MLDE document analysis. The brief presents the salient factors that contributed to the emergence of early adopters of the new data exchange. Specifically, what made these groups want to join? What concerns did they have? How might future exchange organizers build on the interests of early adopters as well as respond to their own issues of concern? This EERC brief is one of a five-brief series that explores the development of the MLDE and details the lessons learned about building and using longitudinal multistate data systems for policy and practice.