Yes, I still fear stigma. Having a more carefree friend (roommate in college) that had the same internship as me helped me meet others, though I keep the actual act of consumption to myself. I fear being judged, but I think that will dull with time, especially in places like CA, WA, CO.
Long story shorter and more relevant: I've picked up a knack for knowing what "hot topics" I can talk about with certain coworkers or friends (or most of all, family). I certainly err conservatively.
As for HN: I've noticed the same trend here. It seems really mixed and it is kind of enjoyable that people still feel comfortable expressing themselves. Reddit has it's dissenters but most people don't say much beyond "I support legalization" even if they disagree with cannabis usage. I've come into more contact with "pot makes you waste your life" types around here, and I'm okay with that. I don't need anyone to judge me, finding happiness in life is an extreme priority for me, so "haters gonna hate" I guess. (But you'll note that my username here on HN is not attached to my real name in anyway as far as I know).
But more directly to the point, if it were to come up at work, I wouldn't have a problem with admitting to using or conversing about legalization. Via my internship my team knows that they can rely on me and I think my work stands for itself. And most of all, I'm really hopeful that my employer isn't interested in my personal life beyond my work. Frankly, if anything else, I've noticed a shocking amount of presumption that I must have smoked because I'd been to college...