I wish there were places to go online to teach or be taught about topics in a discussion-forum kind of way. I'd love, for example, a Lambda the Ultimate for newbs. LtU is an awesome, high-quality site, I just wish I could understand more than 10% of it.
I tend to use HN when I'm too tired to work or just waking up. Those are also the times when I'm not interested in buckling down and studying a hard subject. But surely I could do better than the kind of learning I get from HN (and other casual internet use), which is random access to shallow, scattered tidbits, as if training for a massive Trivial Pursuit tournament you never signed up for. If only there were a community where people devoted themselves to teaching and learning classic topics in a sustained way, but that still had the social and casual aspect. News as such doesn't interest me that much. I'm mostly just consuming it by default. If anyone's read this far - my apologies for adding a mostly off-topic comment to an already crowded thread.