$m or $mm?
I prefer $m.
There is only one 'm' in millions.
While M = 1000 in Roman numerology and M^2 = MM, that's a weak-arse justification and an unnecessary letter.
The second m is redundant. Who the hell would confuse $m as referring to anything other than millions.
Can anyone justify $mm on any basis other than "it's a stupid industry custom"?
Educate me.
