Déjà Dup Mission Statement
Data loss is the most preventable digital tragedy of our time. Our goal is to prevent it as much as possible, by serving those users who would otherwise not make a backup at all.
Ease of Use
Backing up should be easy.
Most people know they should do back up, but few do so on a regular basis. Even the smallest barrier can be too much for a casual user.
Nor is backing up a binary, either-you-do-it-or-you-don't action. Backups can be more or less 'safe.' They can and ideally should be:
Off-site (protects from disasters in one location taking out your primary computer and your backup)
Encrypted (protects from unauthorized access to your personal data, especially since backup locations are not always trusted)
Regular (if you only backup when you remember to, you're not backing up frequently enough)
Being 'easy' does not need to mean 'unsafe.' The above goals can be met without sacrificing ease of use.
Trying to be everyone's One True Backup Solution is doomed to failure. The best experience can be crafted by targeting a specific audience or use case.
Déjà Dup aims squarely at the casual user. It is not designed for system administrators, but rather the less technically savvy.
It is also not a goal to support every desktop environment under the sun. A few popular environments should be supported, subject to sufficient developer-power to offer tight integration for each.