Not sure if we already met when I came in to give Kevin UI feedback a few months ago, but these features are looking really awesome! Very exciting to see the technology progressing like this. Can you give any indication about other classes of problems you’re thinking about applying machine learning techniques to?
For more free-form problem types (written short answer, etc.) I wonder if you could use OCR to extract target keywords for further clustering analysis? It might be at least a rough step towards a meaningful grouping scheme prior to manual analysis.