When I was at #MSMVP: San Diego this past Saturday, I chatted it up with a few people. I told them that MVPs were there to give them a few tips and tricks about the technology available in the Microsoft store. For the employees this allows them to give much more information to their potential customers and help them understand how these techs can work together to improve their life at the office, at home and on the go.

I didn't know that very few knew about the concept of "Buy once, play anywhere". So here's how it works.

You use a Windows Live ID to log into several Microsoft properties. If you're using the same ID for all of it then you're creating one identity that goes across several properties. For the sake of understanding how "Buy once, play anywhere" works you have to have the same ID login for XBOX 360 and Zune.

Go into the Zune Video Marketplace on XBOX 360 and purchase a film. When you do, you are now the owner of that particular piece of content. Head over to your PC, fire up the Zune software and go into your purchase history. If you're using the same ID, you should see that same film available for download to your PC.

So now you have it on 2 of Microsoft's 3 screens: PC and TV. Connect your Zune HD (or Windows Phone 7) to the PC and sync that film to the device. Now you have that film available to you in three different ways: PC, TV, Mobile Device and remember, you only paid for this film once.

This feature works well so that no matter where you are, you have your favorite videos available to you at all times. It makes much more sense now that the revamped zune.net front page has a headline titled "your entertainment, everywhere". "Buy once, play anywhere" is one of those major details that will allow you to keep what you enjoy only a push of a button away.