Luis provides an interesting role model as an entrepreneur. I too often encounter CAPTCHA which causes me stress (“did I find all the street signs?”) – I can appreciate the need for the product and the success achieved. Having a second, follow-on act like Duolingo is very impressive. I especially appreciate the positive social focus with the application and the desire to drive impact on such a large scale. Further, I’d suspect that there is pressure to further “monetize” the app. So, reading here (and elsewhere) about the desires to not distract from the main mission while finding ways to generate revenue speaks to the strength of leadership and vision.