After a few Google Searches, I finally found how to Send an Email, using SharePoint 2010 Designer Workflow, to the Original Creator of a Discussion Item when someone posts a reply to the discussion item.
Here is the original URL I used for the instructions: http://answers.flyppdevportal.com/categories/sharepoint2010/sharepoint2010customization.aspx?ID=03d57a50-17d6-4013-bb58-b816d97f63ec
“I learned that discussions have two different content types, Discussion for a new topic posted and Message for a reply to that topic.
The ID for the original discussion (topic) post is the column “ID” on that item. But the reply messages store this same number in the “Parent Folder ID” column.
So, I created a workflow with one condition, that the content type is Message. When the condition is met (only by replies), I send an email with the To field populated by: “Workflow Lookup for a User”, with the data source as the Current List, the Field from source as Created by and the Return field as Email Address.
Under Find the List Item, the column is ID and the Value is Current Item:Parent Folder ID. Then fill in the body of the email with whatever data you need.”
Note: Condition – “Current Item Content Type equals Message (You’ll have to type in the word “Message”)
For the Action, just follow the picture that shows the correct way of determining the Originator of the Discussion Item.
For the Body, you could add a direct URL to the Discussion List Item from the following Blog Page: http://geekswithblogs.net/bjackett/archive/2011/02/18/sharepoint-designer-2010-email-link-to-item.aspx
Ask if anything is unclear. Thanks for reading.