I have an old idea of mine about a web service (aka "startup") that would roughly do what you described plus some additional features to boost learning/memorizi

I have an old idea of mine about a web service (aka "startup") that would roughly do what you described plus some additional features to boost learning/memorizing the most useful bits of knowledge. But for now we have to live with ReadTheDocs, these days I barely have time to browse Hacker News!