#importより安全で効率的な@import http://stackoverflow.com/questions/18947516/import-vs-import-ios-7
You can use modules with any of the system frameworks in iOS 7 and Mavericks.
iOS7とMavericksフレームワークで使える
you don't need to add the framework in the project settings, it's done automatically.
（＋ボタンで）フレームワークを追加する必要がない
You don't actually need to use the @import keyword. If you opt-in to using modules, all #import and #include directives are mapped to use @import automatically.
別に@importを使わなくても勝手にマッピングしてくれる （昔のプロジェクトを変更する必要なんてない）
Modules only work with Apple frameworks (UIKit, MapKit, GameKit, etc).
Appleのframeworkしか対応してない
Modules are enabled by default in new projects in Xcode 5 . To enable them in an older project, go into your project build settings, search for "Modules" and set "Enable Modules" to "YES".
Xcode5の設定でEnable ModulesをYESにすれば昔のプロジェクトでもそのまま使える
You have to be using Xcode 5 and the iOS 7 or Mavericks SDK, but you can still release for older OSs (say iOS 4.3 or whatever). Modules don't change how your code is built or any of the source code.
Xcode5でiOS7 か Mavericks SDK なら昔のOSでもソースコード変更する必要はない （昔のOSでも使えるって意味だと思われ）
- Imports complete semantic description of a framework
- Doesn't need to parse the headers
- Better way to import a framework’s interface
- Loads binary representation
- More flexible than precompiled headers
- Immune to effects of local macro definitions (e.g. #define readonly 0x01)
- Enabled for new projects by default
Replace #import with @import Cocoa