I can tell you from first-hand experience, though, that if you cannot scale immediately when the time comes, your business can drastically suffer for it.
I don't disagree, but a few points spring to mind. And in my earlier post, I wasn't really thinking about 'scaling', but new functionality/features.
Occasionally "immediately" really does mean "in the next 5 minutes". Oftentimes it actually means more on the order of days or a couple weeks. "Scaling" can mean different things, and anything beyond "scaling" web requests alone will likely mean a shift in business operations that can't/won't happen overnight either.
In most situations where I've been in where people request something, but the rest of the business unit really isn't ready to handle the change. "We need the new data reports now" but when you make the change you realize the other company who pulls the data to process it is on vacation and won't be back for two weeks, and if you make the change now, then it'll break everything.
Yeah. I was only referring to scaling in the sense that the number of users increases. Often, it is easier to implement an application by ignoring scalability, and you can get it out the door quicker.
However, this can be a terrible mistake if your users are not resilient to downtime or lost data (e.g. in the case of Facebook games). Even just a few hours of downtime or slowdown can cause a significant, permanent drop in users.
