It is one of the Nice functionality in Lotus notes...
Simple Readers and $Readers field's functionality is same.
But the Behavior is making me excited...
For a single field which is changed the all of our document's items.
Create a form.,
Without putting "$Readers" field, Run and save for some times :) ( for some documents we have to get)
Put a field on your form as "$Readers"
Enter @UserName as default value for that field...
Save the document and goto your view, and open the all documents and see you will get amazed... (:))
Before opening the document please refresh all the documents using "@Command([ToolsRefreshAllDocs])"