For some time I've known the key to Amazon's current and future success will be the growth trajectory of Amazon Prime. The attack from Wal-Mart confirms it has been making a lot of headway, and presumably is not only taking enough business away from the struggling Wal-Mart to cause the Bentonville company to take this type of action, but shows it is considered a significant future threat as well.

On the other hand, the quick response by Amazon founder and CEO Jeff Bezos to the attack on its flagship business also confirms he can't allow Wal-Mart to take away market share. If that were to happen, I don't see Amazon having the ability to become profitable on a consistent basis. That means this is going to be an entertaining but expensive battle now and in the future.

I'm having a hard time thinking of two companies I'd rather see engaged in a pyrrhic race-to-the-bottom.