It's dangerous to go alone. Take this: http://news.ycombinator.com/item?id=3991859

Once you hit the front page, the time is quite relevant. But before then.. /newest is so poorly visited and read that you're really throwing yourself into the hands of lady luck and hoping there are more than a handful of people who even see your item. (Yep, tons of good stuff doesn't get voted up at all simply because no-one sees it.)

Yes, but, competition is fiercer. The beginning of a business day in the US is also the time when a lot of strong, interesting articles (from newspapers, blogs, etc) are being read by awakening HN'ers and then submitted. They can crowd out your post. But if you succeed, you'll enjoy strong inertia for a long time as people keep coming back when they should be working. Like right now :)

[I think; subjective analysis etc etc]

>"the optimal time is to post to HN."

When you have good content and your luck is at its maximum.

they didn't include HN in their writeup, but the bitly folks had a blog post about this topic pretty recently. They looked at posting times for Twitter, FB, and Tumblr. http://blog.bitly.com/post/22663850994/time-is-on-your-side