I'd not even heard of product hunt, is it a UK only thing?
Another view (a far more accurate view) is that it is a spin-off from Hacker News with a more focused topic. I quite enjoy the site, and I've never posted anything on it. Non-technical people and product focused people can find a lot of the stuff on HN outside of their interests where product hunt hits much closer to the bullseye, more consistently.
I just wanted to clarify that Product Hunt does not appear to be an organically created phenomenon, but a very engineered process that from the looks of things was very well executed.
I could also be completely wrong.