Aspect-oriented Programming and Code Contracts in ASP.NET MVC
There are some aspects to application programming, such as logging, tracing, profiling, authentication and authorization that cut across the business objects. These are difficult to deal with in an object-oriented paradigm without resorting to code-injection, code-duplication or interdependencies. In ASP.NET MVC, you can use attributes in the form of action filters to provide a neater way of implementing these cross-curring concerns.