And to further clarify, the choice use of the word "replaced" in the OP-submitted headline implies Jason was pushed aside or something, which is very much not the case.
This is something that has been in the works for some time, even before Heather was brought on as COO in the Spring.
Managing a company is a lot different than starting a company. I think that's what Cohen is getting to here: he was good at growing the company in the beginning, but managing a company of 80 people is a completely different job description.
This is a smart move and it is the sort of answer to the question, "do you want a big piece of a small pie or a small piece of a huge pie?" that every founder must decide for themselves. Ultimately the best thing is to put yourself where you can do what is best for your business, but sometimes that means not being in charge.
I'll pretend your question is genuine. It's because of his thoughtful explanation of how the CEO role changes as startups become established businesses. (Not because of the notoriety of his business-- which I assume is the source of your sass.)
Jason Cohen's blog (http://blog.asmartbear.com) has historically been very popular among the startup crowd and used to be regularly front-paged on hacker news. Also, WP Engine is popular and many of us use it. Note that they host the blogs of several well-known tech companies.
This makes sense. Like he said in the post, as a company grows, the CEO role tends to shrink farther and farther from the technical nitty-gritty.