rvm (an open source tool for managing your Ruby environment) had a crowd-funding campaign: https://www.bountysource.com/teams/rvm/fundraiser
They collected all the cash they needed, the maintainer took a break for some time, and now they're working on the next major release.
If a website using https (HN) points to a website not using https (the blog), then the referer is hidden. So it's not something HN is doing specifically, it's just because one is https and the other is not.