Update, June 2016: GitHub recently announced official HTTPS support for github.io domains on GitHub Pages! This is excellent progress, especially because for new github.io sites, HTTPS is mandatory. Existing github.io sites can opt-in to server-side HTTPS enforcement. Of course, the work's not done until GitHub Pages supports HTTPS for custom domains. But this is clearly involved a ton of CDN and
![GitHub Pages Now (Sorta) Supports HTTPS, So Use It](https://cdn-ak-scissors.b.st-hatena.com/image/square/63796ac05c5e4369285868fdea49684bec5feb1b/height=288;version=1;width=512/https%3A%2F%2Fkonklone.com%2Fimages%2Feric-mill-headshot.jpg)