I actually love it when a developer says something like this, because it tells me way more than even 2 full days of pairing or interviewing could: They know absolutely nothing about software at scale, and are probably extremely arrogant to boot.
It informs me that you're probably a JQuery developer, personally offended because you believe that your work is incredibly advanced and challenging. In reality, what you do is probably some of the easiest "coding" to have ever come to fruition. Yet, you toss out the "at scale" comment ad nauseam because you think it'll make you sound important.
Just by the fact that you denounce anyone who recognizes the simplicity of it modern development tools shows me you probably fail to recognize the simplicity yourself. Or you don't want to admit the simple fact that programming has gotten much easier. That's been intent of so many modern languages, yet we're always going to have someone like you who claims we all don't know what we're talking about because we've never built anything "at scale".
Your 10,000 hits / day blog isn't "scale" buddy.
Edit: Also, I'm not your buddy, pal.
Jokes aside - the biggest error this software developer makes is not realizing that software is not the crtitcal part of AirBNB success. It is the thousand manyears of boots in streets promoting the app and getting people onboard.