When Apple killed MobileMe and iDisk I was pretty unhappy. It was great for quick small backups, and an easy way to share files with friends by giving them access to a public or password-protected folder.
There are plenty of sync/backup solutions out there, like MediaFire, Dropbox, SugarSync and others, but I really liked the desktop mounted iDisk, that looked and acted like an external drive. Other similar options include Google Drive,
