I started using it several years ago, when I realized I was falling behind on keeping up on my professional knowledge, and had gotten out of the habit of knowing how to study. Now that I’m using it, I think I’m a better student than ever. I not only use it for professional knowledge, but also general knowledge (misc bits of whatever that I want to learn), French, and more recently Vietnamese. The jury is still out on that last, but overall, I find it a great learning tool for facts.