One of those apps is OneDrive, though it got BIG love from Microsoft last year, a key feature still missing is the ability to access files offline.
Thanks to a uservoice suggestion.. Microsoft has responded and noted that this feature is already in the works, though no ETA on when we will get it. This piece of info is courtesy of Microsoft's Program Manager, Casey Penk who was responding to a user query on this missing feature.
There has been rumors that OneDrive will soon support the ability to play music from your OneDrive. This offline access looks to be tied into this upcoming feature.
Maybe we might see it in action in a couple of weeks at the Microsoft Press event.