As hypermedia, online teacher professional development (TPD) should ideally support diverse learners to work with online content effectively because it involves multiple representations and a nonlinear format. Differences among participants in motivation and learning provide challenges for design. The present study is a use-inspired, mixedmethod study of 164 teachers' motivation and learning in an unmoderated online workshop. It addresses participants' demographic and motivational profiles, participation in this type of workshop (e.g., the frequency, duration, and focus, as well as their work with technology-enhanced, nonroutine challenge problems and journal assignments), the predictive value of the initial questionnaire, and implications for design. Findings indicate that while three clusters of motivational profiles could be identified (low interest, low selfefficacy, and less math; low interest, high self-efficacy, and more math; high interest, high self-efficacy, and more math), whether the teachers continue to participate appears to be related to the structure and content of the workshop, not just these profiles. Findings are interpreted as suggesting that the potential of hypermedia lies in its designers' abilities to support participant stake by providing for multiple ways into thinking and working with disciplinary content-design that both accommodates and supports those with differing strengths and needs. Implications for studying motivation and learning online are also discussed.