Just today or yesterday, Math SE's MathJax libraries are no longer loaded from mathjax.org but from cdnjs.cloudflare.com. mathjax.org explains that they are shutting down at the end of this month. But I was wondering, why is StackExchange not just getting a local copy instead of relying on a CloudFlare distribution? After all, it's little compared to the amount of data in StackExchange itself. Am I missing something?
After all, it's little compared to the amount of data in StackExchange itself.
Yes, you're right; Stack Exchange wouldn't notice if they need to serve an additional library like this. However, one of the main advantages of using a central distribution, like CloudFlare, instead of hosting it yourself, is that users are likely to visit multiple sites using the same library. If you visited another website which is using CloudFlare to host MathJax, it doesn't need to be downloaded again when you visit this site. This improves page loads and user experience, so the ultimate benefit is for the user and not for Stack Exchange itself.
Well, if SE goes down, even temporarily, it wouldn't matter where the math rendering is loaded from. But if the math rendering goes down for whatever reason, you still have access to the text version and the interactivity that SE provides, along with readable LaTeX, without the pretty math rendering. So there is an advantage in that.
Also, it reduces the work load of SE servers. This makes SE a more stable and reliable site for the raw content. Different servers then can be optimized for certain uses.
Separate servers devoted to math rendering that can be used on any site helps to standardize the aesthetic, code, etc.