This paper uses student perspectives on learning to highlight the potential contribution of the WikiRate platform to develop knowledge, skills, attitudes and sustainability mindsets of future business leaders. WikiRate originates from a project with a mission of "crowdsourcing better companies" throughanalysis of their Environmental, Social, and Governance (ESG) performance. The project identified a need for an open public repository of data tracking companies' ESG performance, on the grounds that while corporate social responsibility reporting is conducted in public, there are barriers to accessing information in a standardised format. WikiRate provides an open repository for data along with tools for analysis, allowing business students to participate in its interpretation. Seeing potential for this pedagogical innovation to help develop the next generation of responsible managers and leaders, educators in business schools in five countries carried out a survey of 1575 student users of WikiRate to explore what they had learned. Analysis of responses from 549 students using a grounded theory approach found that WikiRate extended students' knowledge, skills and attitudes on several dimensions. The findings suggest that use of WikiRate is a valuable addition to a growing number of open source platforms designed to contribute to the development of competences for sustainability.