I honestly clicked that thinking (and hoping) it would be an article discussing the different types of water filled ditches, used as a defensive barrier.

https://en.wikipedia.org/wiki/Moat

Same here.

Moats (water filled ditches, used as a defensive barrier) are cool! Especially the ones with Alligators in them.

Does someone have a link for taxonomy of real moats?

Not a taxonomy, but you might like it anyway. https://twistedsifter.com/2011/05/impressive-moats-around-th...

This was great.

I wrote some thoughts on a subset of what is discussed in this article, the knowledge moat:

How to Make a Good Secret Sauce:

https://medium.com/swlh/how-to-make-a-good-secret-sauce-8773...

And follow up: Product Market Crossfit: https://medium.com/@b.essiambre/product-market-crossfit-c09b...

I'm not sure I do a good job of laying out my thoughts. I'm interested in feedback.

I like the idea of complex knowledge being protected in code.

But what happens when a key employee leaves for a competitor ?

Well, key employees are a weakness of knowledge moats since some of the knowledge gets embedded in them. This might explain why people are paid well in knowledge industries, to prevent them from leaving.

The part of the knowledge that is embedded in code usually doesn't leave with employees. This might be an important advantage for software companies, a lot of the expertise gets embedded in the software platforms.