Here's the link to the ExplainXKCD about this image.

The one mentioned is the node.js story. It wasn't a long term thing, as it was just a matter of replacing the code and many had their own local versions and weren't relying on a core source like others that broke. But dependency, no redundancy, not breaking gracefully, they all are avoidable problems that are all around waiting for whatever little block topples for them.