A column template is a collection of well-known instances of particular fields—in other words, a shared field definition. A shared field includes settings for that field, such as the set of choices for a choice field, or whether rich text is supported for a text field.
An example of a shared field would be "Specification Status," which has standard choices such as "One Page," "Draft," "Reviewed," and "Inspected." Each team in a deployment can reuse this custom property definition on their site.
Shared fields are a provisioning concept referred to by content types, such that if you provision a site collection with two separate content types that use the same shared field, the provisioning script for those content types instantiates the exact same field, and each field instance shares the same unique identifier.
· Farm: No
· Web Application: No
· Site Collection: Yes
· Web Site: No
For general information about column templates and how they function within Windows SharePoint Services, see Introduction to Columns. For information about the file format used in column templates, see Content Type and Column Template Definition Files.
· Fields: http://msdn2.microsoft.com/en-us/library/ms426306.aspx
· Introduction to Columns - http://msdn2.microsoft.com/en-us/library/ms450825.aspx
· Column Definition Schema Overview - http://msdn2.microsoft.com/en-us/library/ms459922.aspx
· Field and Field References - http://msdn2.microsoft.com/en-us/library/aa543680.aspx
· FldTypes.xml - http://msdn2.microsoft.com/en-us/library/ms469928.aspx
· Updating Site Columns - http://msdn2.microsoft.com/en-us/library/ms466937.aspx
· SharePoint 2007 Features – Creating Site Columns and Content Types - http://sharethispoint.com/archive/2006/07/17/11.aspx