> 6. iCloud is the most popular target because Picture Roll backups are enabled
> by default and iPhone is a popular platform. Windows Phone backups are
> available on all devices but are disabled by default (it is frequently enabled,
> although I couldn’t find a statistic) while Android backup is provided by
> third party applications (some of which are targets).
Not really, of course. The big win (shared by Windows Phone) is simply not turning on the security-sensitive cloud service by default. That being said, it is worth noting that enabling/encouraging third-party service competition can create an extra hurdle by discouraging cloud-service monocultures.