justcloud

Provides a wide range of features that are both easy and effective.
Backups on a specific schedule, such as daily, weekly or monthly or initiate automatic backups to any changed or new files added to a backup folder.
Useful file sharing capabilities allowing sharing for files or entire folders by email, Facebook or Twitter, or you can create custom, private links for specific files to send to recipients.
File versioning allowing restoration of previous versions of your files in the event of accidentally deleting the latest version, and the service keeps a detailed history of all your actions.
Also it doesn’t limit the size of files you can upload, while also providing file preview before downloading it.