TL;DR: the CLI is the specification, of which the CLR is Microsoft's own implementation. Another/the other implementation of the CLI is Mono.
Which begs the question: you've written "Microsoft's CLI", which does make sense because they were the ones who've come up with it, but can't that be interpreted as a synonym for CLR? Maybe that's what 616c meant.
Sorry, my bad. I had no idea about CLI, and the CLI-CLR distinction, or I would not have put foot in mouth. Thanks for the link and not a snarky comment.
