NOTE: If you haven't read the first post in this series, I would encourage you do to that first, or check out the Sharepoint category. You can also always subscribe to the feeds.

The Sharepoint 2007 System introduces two types of pages the first type usually called Application Pages and other type called Site Pages.

As a sharepoint developer you should know both of these types of pages and when to use them, so let me define them here briefly and show some differences between them to help you decide which type of pages you will want to use when developing in sharepoint.

Application Pages

Application Pages are non customizable and are found in  the C:\Program Files\Common Files\Microsoft Shared\web server extensions\12\TEMPLATE\LAYOUTS, its worthy to note that this physical directory is mapped to the virtual _layouts directory whenever WSS/MOSS creates a new Web application in the IIS. By using this mapping scheme along with some additional processing logic, the WSS/MOSS runtime can make each application page accessible within the context of any site in the farm.

When building custom application pages you should use the Microsoft.Sharepoint.LayoutsPageBase as a base class and should be content pages that reference to the ~/_layouts/application.master master page, Application Pages might include in line code or have a code behind file compiled in a dll, to deploy application pages they should be the LAYOUTS directory and all custom code dlls either in the GAC.More...

A new feature in the Sharepoint 2007 is the "Feature" development style which means that every tiny and huge development task in the sharepoint is considered a "Feature".

Features can be activated or deactivated through a site administrator, which enables the very simple turn on/off of anything in the site.

Features are used for developing anything starting from a small button to a full site definition and tons of files and functions including webparts, workflows, lists, pages, content types, document libraries and others. I will try to include the development of all these topics in this series wish me luck and provide feedback. More...