Being able to pin a set of requests to a specific path inside the infrastructure to they touch only specific instances running specific versions without adding "if blah-blah-blah" custom code into every deploy

Being able to trace every request across the entire infrastructure including all sub-requests the original request triggered.

Being able to observe issues pinned requests caused, automatically trigger an action when an error rate exceeds the threshold, typically removing the pinning.

I'm asking myself the same thing... but I think he is referring to Load Balancing and Logging and maybe Public Key Pinning? Not sure... I'm however sure that Google and Facebook are not the only ones who do Load Balancing and Logging and therefore aren't the only ones who can benefit from CD :)