Will we be able to buy music on Blu-ray?

No, Blu-Ray is not a media providing service like YouTube or iTunes. Blu-Ray is more like the next DVD. It is a different type of formating that allows data to be written tighter, taking up less space on the disc. This allows for much more data to be stored on each disk. It also has the benifit that it allows for high quality images. It will store all of the information in a High Definition format.