The purpose attribute accepts a text string which will be displayed in the Purpose column of the View List window.  In systems with many views it is helpful to use this attribute to provide users with information about each View's purpose.

For example,
"This View is used to create Staff Bio links on the About Page"
"This View exposes employee salary information for members of the Human Resources Group"

This example:
<View Id="Volunteers" TableId="Contacts" Purpose="This GROUPS View applies to the Interns Group">

Creates the following display: