The only thing I'd add to this article is that in the earliest stages of the company (where there's just a handful of people), the CTO is also the VP of Engineering and also the programming lead.
True at our company of two both the CEO and CTO are the programmers. CEO does a little more with the business side of the world. CTO spends a little more time on architecture. I assume the roles will become a little different and more defined as the company grows