Crystal Knows is a #browser-extension which helps you understand those with whom you communicate by predicting their personalities. [1] Crystal uses Machine Learning (ML) to predict the personality based on analysis of public, written information and coaches you to write more effective emails—providing personalized email advice, templates, and even real-time suggestions. [2]
I love the concept of Crystal, but found that—since the machine learning develops its assessments from publicly available information and thus creates a personality derived from a presentation of oneself—it was easy to become dangerously dependent. For this reason—and the sluggishness of the load times—I no longer use Crystal, but still recommend playing with it for a few weeks.
References
Crystal Knows, crystalknows.com
Crystal Knows: Sales, crystalknows.com