Allard's Puzzling Times, Oli's Mechanical Puzzle Blog, PuzzleMad, and Jerry's Small Puzzle Collection), but I tried not to read too closely for fear of getting accidental hints.
I fiddled with it on and off for a few days, rotating the lid this way and that and shaking it around. I felt that I had a fairly good idea of how it was supposed to work, based on a few observations, but I couldn't quite figure out how to accomplish it.
At one point, I thought that pressing the lid down onto the base might be helpful, and indeed it did cause the lid to spin less freely. Unfortunately, it eventually seized up completely! With quite a bit of muscle and cursing, I managed to free it, but I was quite worried that I had ruined it. Just to make sure I wasn't on the right track, I emailed Oli to see if that type of motion was required, and he assured me that it was not.
With a bit more puzzling, I was able to get it to open: indeed it did open the way I expected, but it took me a little while to figure out the method needed to do so. When I had it open, I could see what a mess I had made of things by pressing the lid down on the base: the lip where they meet had gotten all chewed up! Fortunately, I was able to clean it up pretty good with a file and some sandpaper. Using increasingly fine sandpaper (used for returning the clarity to acrylic windows), I had the finish looking as good as new, aside from a few pits that were fairly deep. Don't squeeze the lid down!
The mechanism itself is quite precise and well crafted, as well as being an interesting concept. It is one that you could spend quite a while on if you don't come up with the correct idea, but you may guess it fairly quickly if you have a knack for this sort of thing. Overall, a nice little puzzle that I'm glad to have purchased, but I probably won't be tormenting any of my guests with it, since it is quite challenging!
29 minutes ago