I don't know what the big deal is scaling up. I have worked in a couple of "big scale" apps and it's really simple principles. At the end of the day, it's all about caching, powerful machines, caching, normal coding skillz, caching. And oh did I mention caching?<p>I honestly don't think it's that big a deal to 'scale'. Programs like early wolf3d impress me more, much much more. And of course, things like the recent quine relay leave me demoralized.