There are lot of use cases wherein 'dedup' helps, and it could be done in a number of ways. For eg: Lets say there is a huge email attachment and it needs to be

There are lot of use cases wherein 'dedup' helps, and it could be done in a number of ways. For eg: Lets say there is a huge email attachment and it needs to be sent to everybody in the company. Instead of saving a copy of the attachment in everybody's account, only one copy could be saved and others could point to this. Mail systems probably already do this. However, if this support natively existed in the file system layer, application developers could take advantage of this feature instead of rolling out their own 'dedup' applications.