You and several other people are completely failing to read and comprehend the blog post in its entirety. This has nothing whatsoever to do with where USERS are

You and several other people are completely failing to read and comprehend the blog post in its entirety. This has nothing whatsoever to do with where USERS are connecting from. If you have X sessions on a single front-end server opening one or more individual connections to a single back-end server (e.g. CouchDB), at least X ephemeral ports are used on the front-end server to connect to the back-end server. As X increases, you can reach a point where you have a serious problem. If X gets anywhere near ~60k, it's game over.