Second, Keybr.com measures your keystroke dynamics and collects comprehensive typing statistics. For example, it measures your typing speed for each individual key, and uses this data to generate random words putting emphasis on the weakest key. The more troubles you have with a particular key, the more you will be typing it. It means, the generating algorithm will put that letter in every word in the next generated lesson. Your typing skills are re-evaluated after every completed lesson, and the next lesson will be adjusted accordingly.