[amenhotep]

> Or, is the character not rotated, but just written in columns not rows?

This one. Think about it - they don't expect the reader to tilt his head 90 degrees to read it :)

[dfee]

Formality is often tied to skill. Writing at a 90 degree angle would require more skill, the ability more rare.

Calligraphy, for example, conveys no extra information but is of higher stature.