"It's obvious to me that "anonymous" has chosen his own definition of tempo"

Anonymous was very adamant that he/she WAS NOT DEFINING TEMPO.

The metric used was NOT TEMPO, instead it was the APPLICABLE SPEED OF THE DANCE.

BPM is a measure of TEMPO only. On the other hand, MPM is a measure of tempo, but also, for some common dances (especially Jonathan's example waltz vs. foxtrot) a measure of the SPEED OF THE DANCE.

BPM leads to false conclusions about dance speed. MPM leads to valid comparison - a waltz at 40 mpm is a heck of a lot faster than a foxtrot at 30 mpm. Dance the same material in both, and look how alarmingly wrecklessly you would have to fly in that waltz.

Anon. You are absolutely right. I will add that on this very excellent site if a person will look to their left will see The Learning Centre and Learn the Dances If you have not got Quick Time loaded it is there free and easy to load. You will need this to see the videos.