More quotes from Semiotics for Beginners:
Different media and genres provide different frameworks for representing experience, facilitating some forms of expression and inhibiting others.
… the more frequently and fluently a medium is used, the more “transparent” or “invisible” to its users it tends to become. For most routine purposes, awareness of a medium may hamper its effectiveness as a means to an end. Indeed, it is typically when the medium acquires transparency that its potential to fulfil its primary function is greatest.
I’m thinking about expressive universes here, which indeed should be transparent when they have been established.