Yes, early in the article it says "Facebook has northwards of 800 memcached servers creating a reservoir of 28 terabytes of memory enabling a 99% cache hit rate

Yes, early in the article it says "Facebook has northwards of 800 memcached servers creating a reservoir of 28 terabytes of memory enabling a 99% cache hit rate." I've covered this stuff before so I don't explore the topic. It's a device to quickly show how memory is being used by serious companies to do serious things. Caching is mentioned as related to but not the same as SoR, but you are right, I don't spend a lot of time on it. I understand why you wouldn't be keen, but it is at least something to think about.