CodeIgniter is scaled by mass because it is very small. It may seem a little ridiculous coming from a CodeIgniter enthusiast, but that is why I love him.
CodeIgniter is ridiculously light. It has no agreements, no real overhead and was recommended by Rasmus as the easiest structure around.
Scalability is the increase in your application, traffic, performance, and overall size. The overall size does not matter, since it only downloads what you download, the traffic is fine with some proper caching, and the performance works brilliantly, as I already pointed out: it is light as hell.
I have tons of websites rated at 100,000 or higher on Alexa, and they have not yet fought.
Phil sturgeon
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