[muzani]

Most of these were actually ditches. Ditches stopped cavalry or redirected them. The water is unnecessary. They were also dug on the spot, like hours or days before battle rather than around a fortified castle... a little ditch just messes with movement drastically.

I like the analogy of ditches though. Network effects fall apart quickly. I signed up for Spotify/Netflix/Google Premium with my family, but I unsubscribe as a family too.

Just add something that slows down the competitor. Software giants are like cavalry or battle tanks. They're expensive and unstoppable, but they can't go uphill very well, and you should be just throwing a few obstacles here and there instead of entrenching yourself.