The web/application layer
The web/application layer is composed of whatever happens between receiving the request from the client and sending back the response (or querying the DB layer to get the required data). Most of the web/application layer will be in a server-side language, such as C#, so when you try to optimize the web/application layer, you need to incorporate the best practices of ASP.NET MVC and C#.
No business logic in Views
A View is what is rendered to the browser, and it can contain presentation logic. Presentation logic represents where and how the data is to be displayed. ViewModels (actually, models specific to the View) are models that hold the data for a particular view.
Neither Views nor ViewModels should contain any business logic as this violates the separation of concerns principle.
Look at the following Razor View code. We are just looping through the list in the model and presenting the data in tabular format—nothing else:
<h4> List of employees:</h4...
