Thought-provoking essay on the hidden value of personal projects:
All of these properties of personal projects suggest they’re a really good predictor of talent that is worth hiring. Though this approach may suffer from the occasional false negative (even the greats now and again bang out quick-and-dirty personal projects don’t necessarily impress), a false positive probably never does: you’ll probably never find someone with a great personal project who also turns out to be rubbish.