If you take the time to sign up to this blog, I can promise you that I will never use your information for evil. I'll definitely look at it, because I'm a curious sort of person, but I won't sell your information to anyone else. Hell, I won't even give it away. I'll only use it to email you about blog posts that I make, which, as far as I can tell, is the intent of the system.
Additionally, because Ghost doesn't give me any intelligence as to which pages are being viewed and how often, I've also incorporated Google Analytics into the site. Specifically, just the page views part, but lets be honest, Google Analytics is a bit of a beast and I certainly don't understand it completely, so I'm mostly just hoping it doesn't do anything shady.