Deciding Between Custom Web Templates and Custom Site Definitions
Applies to: SharePoint Foundation 2010
We recommend that you construct Microsoft SharePoint Foundation solutions as one or more features, possibly including one or more Web Parts, whenever possible instead of creating a custom site definition or custom web template. Doing this maximizes flexibility both for you as a developer and for your users.
However, if a custom site type makes the most sense for your solution, the next question is whether to create a web template or a site definition. To maximize the chances that your solution will be compatible with future versions of SharePoint Foundation, we recommend that you create a web template. Some other advantages of web templates are the following.
Custom web templates are easy to create.
Almost anything that can be done in the user interface can be preserved in the template.
Custom web templates can be modified without affecting existing sites that have been created from the templates.
Custom web templates are easy to deploy.
The user context in which a web template is deployed does not have to have access to the file system of the servers.
However, in the following scenarios (which are not common), you must create a custom site definition.
The custom site type requires new document template for document libraries. (But note that the recommended way to add a new document type is to create a custom content type instead of a new document template in a site definition. For more information, see the Content Types node of this SDK.)
The custom site requires a custom email footer.
The custom site type requires a custom "component" of the type itemized in the Components element of an onet.xml file, such as a custom file dialog post processor or a custom external security provider.