Yang, Seungwon, et al. "Uncovering trajectories of informal learning in large online communities of creators." Proceedings of the Second (2015) ACM Conference on Learning@ Scale. 2015.

This study explores informal learning within the Scratch Online community, boasting over 4.3 million users and 6.7 million user-generated projects. By modeling learning as a trajectory of programming block usage among users who've created at least 50 projects, and employing K-means++ clustering, the research identifies four distinct learning patterns among users. These range from rapid learning to minimal improvement, providing a quantitative analysis of informal learning that could be applied to other online communities. The findings offer insights for community administrators on tailoring interventions for specific user subpopulations.