This question is about the net speed.
I'm from China, and I find that opening pages on Stack Overflow is very fast, normally within a range of 1 to 4 seconds. This speed is very good for a website outside China; it's even faster than some native websites.
Not every website outside China has such good speed, so I am wondering why and how Stack Overflow manages to be so quick.
Because the developers care about optimizing these things. They recognize that performance (speed) is a feature, and an important one at that. It's all about the details, the same reason why Google is famously fast.
For example, they worry about the size of the code that the client must download, even going so far as to compress aspects where the compression has a demonstrated benefit on download speed (but also carefully benchmarking to get the most bang for the buck). And they constantly evaluate better content delivery systems and switch providers to attain the maximum performance possible for all users. And, of course, a well-designed and well-implemented design/stack is vital as well, along with taking care to hire smart programmers and provide them with the right tools to do their job as effectively as possible.
See also: A day in the life of a slow page at Stack Overflow posted on one of the developer's blogs.
See what I mean?
I believe this is the primary advantage of using a Content Delivery Network or CDN solution:
Note this question: Help us test the advantages of using a CDN
