Merit in this examination for sure, but I would have used the StackOverflow vs ExpertExchange comparison to argue the exact opposite side. Maybe there's some gray area of where code and marketing begins and ends. Site UX, flow, the subtle bells and whistles, design patterns and iterated, tested UIs are code to me.. and this what make Stack what it is.
Stack overflow got exposure to thousands of developers from day one thanks to Joel/Jeff. If they'd stuck the site up anonymously it would be nowhere near as well used now, and might even have never got anywhere without an initial critical mass of users and questions/answers.
The UI might keep users interested once they're there, but it's not going to get them there in the first place.
