Naysayers: "Scaling up free, automated TLS issuance is impossible."
Let's Encrypt:
Quick stat check: % of web pages loaded by Firefox using https: more than 90% in the USA.
Quick stat check: 340,000,000 domains active 😎
May the fourth -- and free Let's Encrypt TLS certs -- be with you!
https://letsencrypt.org/getting-started/

Getting Started
Let’s Encrypt issues certificates through an automated API based on the ACME protocol.
In order to interact with the Let’s Encrypt API and get a certificate, a piece of software called an “ACME client” is required. No part of the process for getting a certificate happens on this website, which is merely informational.
The first question to answer for people who want to get started with Let’s Encrypt is: will my hosting provider get and manage certificates from Let’s Encrypt for me, or do I need to run an ACME client myself?