Whats wrong with iDisk?
Apple’s iDisk is a service that allows the sharing of common files on Apple’s servers on the internet — it is part of Apple’s Cloud computing. While it solves the two problems of speed of access (as it keeps a local copy of files) and offsite storage, it has the same collaborative problems as file servers i.e. if two people edit a file at the one time a synchronise error will ask which one you want to keep (the other is deleted). It also has no sub-account security – if you can see one file, you can see them all.