Tack on post:
Lastly, the lure weight is a range that is pretty subjective, but also gives you a hint to it's actual power. A bass MH may go up to 3/4 oz. whereas an musky/pike MH may be more. When moving up and down the tapers, the weights may change a bit too. I can throw some pretty light stuff on a medium-moderate rod, far lighter than a medium-extra fast. That doesn't mean that medium moderate has any less power than the medium-extra fast.
All three attributes are both marketing and informational, and there to help describe the rod to the consumer. Most companies are doing their best to rate their rods, but it is not an exact or standardized science.