If we want to master a skill, we need to repeat some exercises over and over again. Sports, music, painting, they all require practice to reach perfection. But they all have in common a physical, concrete, activity (also writing would fit into this category). What happens when we want to extrapolate this to learning or thinking?
We can propose a system of spaced repetition also for those processes. This is what quantum.country tries to achieve. You will be asked questions based on what you are reading and you have to judge by yourself whether you remembered the answer or not. If you did, then those questions are sent to the back of the pile, if not, they will be kept in the front.
The idea is that the question will pop up again some time later. If you didn't remember the answer, it will appear soon. If you did remember the answer it will appear again later. The time of re-appearence compounds, if you remember the answer to a question there's no need to refresh it again tomorrow, if you still remember it after a week, you can push it forward to the next month and so forth.