One of the most dramatically psychoactive chemicals known to mankind, so naturally the top comment on HN is the placebo one. Which is always the top comment about things that are thought to have real effects.
But even if most of microdosing is just a placebo effect, I think that's still amazing in itself. Even if you're not "physically tripping", you've willed yourself into a "more open" mental state, creating your own positive side effects.
Placebo effect has real effects. Micro-dosing: Unverified.
However lower potencies, specially in the decimal scale definitely have enough of the original remedy in them as to qualify as a microdose. If you start with a gram, then a 6x potentization will result in about a 1 micro-gram dose, which is about the same as being discussed in this article. And a lot of homeopathic remedies are administered at the 3x or 6x potency as well.