Corporate benefits of facebook

A recent Computing magazine article made the case for Facebook in the Enterprise. As well as the usual points around digital natives expecting to use these tools as business communication applications, Mark Samuels adds one I hadn't thought about until now - Storage Space.
The argument goes that instead of storing personal messages and photos on corporate systems, employees should be encouraged to place them on Facebook. I have certainly worked in organisations where entire file servers are dedicated to sharing mp3 files (although I don't think Facebook would be too happy if it's services were used to share illegal files) so this did cause me to pause for thought.
It doesn't grab me as a silver bullet for corporate use of Facebook though. I'd be interested in just how much corporate storage is used for personal media - my intuitive belief is not much but would happily be proved wrong. Is lack of storage really such a concern for organisations at the moment and does personal media take up such a percentage that offloading it to Facebook would make a difference? Doesn't really work for me...