Quartz – Nikhil Sonnad 
There is a moment in every modern language learner’s studies when they discover spaced repetition systems (SRS) and think, “I have been wasting a lot of time by not doing this.” SRS is learning system that makes the nitty-gritty of studying hundreds of new pieces of information—say vocabulary words—more efficient. If you’re learning a language, you should be using it. (more)