Live messenger has made a really cool marketing push. Everytime you use messenger you support a cause of your choosing. You can choose from 9 causes. At least you can in the US.
All you have to do is add the cause' tag to your name in messenger. Instructions
Yes it is marketing but it is also so much more. And it is well in line with Microsof tbeing the company in the world tht donates the most amount of money to all kinds of causes.