I remember posting what was a rather critical attack of the Microsoft Points system. Just days later I was posting a retraction on that critique. It has been many moons since I realized the value of being able to acquire points or even used those points across the MSN\Zune\Xbox eco system.
I recently entered the MSN autos Design Challenge. I was immediately eligible for 100 microsoft point (about 1 song) for submitting a design for the Dodge Challenger. I can also gain as much as 2100 points (about 2 1/2 albums worth) by providing feedback on other car designs.
I am always concerned with closed economic systems that do not allow you to take the full value of items you have acquired into the real world. I have, however, committed to using the points I acquire to purchase MP3's in the Zune Market Place. That is the only valuable item that I can find that is truly independent of the Microsoft eco system.