In terms of value per person probably improving the faceted search marginally on one of the biggest auction sites in the world. In terms of the impact I care a

In terms of value per person probably improving the faceted search marginally on one of the biggest auction sites in the world. In terms of the impact I care about, I try to give aspiring programmers my time and talk to them about how they can improve their hirability by building useful skills that you'd use day to day. I haven't had much success, but the little success I do have was helped in large part by an influential mentor. Those can be hard to come by, and time is expensive.