Clear Explanation of Concerns & Core Concerns & Cross-Cutting Concerns

As you probably know, Practice & Patterns's teem of Microsoft recently has released
Microsoft Enterprise Library 5.0 and Unity Application block 2.0 .

These versions of the products in opposite of prior versions have very great help and documentations (at least in my opinion!)

Unity Application block 2.0 is very cool library and one great Ioc Container. in a section of documentation exists a short explanation of "Concerns" & "Core Concerns" & "Crosscutting Concerns". I think explanation is just simple and clear.

Taking look at this library & documentation is recommended for Dependency Injection's fans.

" The features and tasks implemented in applications are often referred to as concerns. The tasks specific to the application are core concerns. The tasks that are common across many parts of the application, and even across different applications, are crosscutting concerns. Most large applications require services such as logging, caching, validation, and authorization, and these are crosscutting concerns.

The simplest way to centralize these features is to build separate components that implement each of the required features, and then use these components wherever the management of that concern is required—in one or more applications. By using dependency injection mechanisms, such as a Unity container, developers can register components that implement crosscutting concerns and then obtain a reference to the component at run time, without having to specify exactly which implementation of the component is required."