You can use SharePoint designer workflow to create a worklow and send an email to the user based on the value entered in the column.
there are different ways /logic for creating the Form and workflow, and here is an approach -
- Create a list
- create a workflow based out of SharePoint Designer 2007, then choose to Automatically start the workflow on Item created
- Then inside the workflow, create a new step
- Add a condition to check the field equals value (in your case if the username has some value or not empty)
- then add workflow action to send an email to the user to prompt to finish the Form/Survery
here are some references on SPD workfow
http://office.microsoft.com/en-us/sharepoint-designer-help/create-a-workflow-HA010100591.aspx
http://msdn.microsoft.com/en-us/library/cc627286(v=office.12).aspx
here is a link for custom list form -
http://office.microsoft.com/en-us/sharepoint-designer-help/create-a-custom-list-form-HA010119111.aspx
Hope this helps!
Ram - SharePoint Architect
Blog - SharePointDeveloper.in
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