Compatible with iPhone or iPod Touch. Requires iOS 4.0 or later. For note syncing, you need a Simplenote account.
Simplenote is the most successful cloud service for note taking. There are many mobile, web, and desktop clients that support it. You don’t need to install Simplenote iOS app to use Hidden.
Note privacy is the important issue on iPad. We’re working on iPad version; it will be released as a universal app, so you don’t need to buy the app twice.