First, let’s understand the main different between Application Pages and Content Pages:
- Content Pages – Contains content controls that can be modified by end users.
ONLY Content Pages can contain Web Part Zones, therefore can contain Web Parts.
- Application Pages – Are regular ASPX pages that exposed in every site collection or sub site under the _layouts folder.
When we understand these main differences it is easy to know when to use each page, For example:
Scenario A – Content Pages
You need to create an RSS to show relevant content to users in a certain group and you need to support customization by sites administrators and personalization for end users.
Scenario B – Application Pages
Your company wants to provide a central page that displays the latest articles from Eggheadcafe.com. This page will be available for company employees and could not be configured by end users or sites administrators.