You can edit the email templates in the usual manner with the Language Editor (Local Resources -> DesktopModules -> Smart-Thinker - Wall -> PostEdit.ascx).

These are the language strings that you need to edit (depending on which Wall type and notification you want):

NewPostNotificationEvent.Body, NewPostNotificationEvent.Subject -> Used for the Event Wall Type when a new post is made

NewReplyNotificationEvent.Body, NewReplyNotificationEvent.Subject -> Used for the Event Wall Type when a reply is made (to an existing Topic)

NewPostNotificationGroup.Body, NewPostNotificationGroup.Subject -> Used for the Group Wall Type when a new post is made

NewReplyNotificationGroup.Body, NewReplyNotificationGroup.Subject -> Used for the Group Wall Type when a reply is made

NewPostNotificationUserProfile.Body, NewPostNotificationUserProfile.Subject -> Used for the UserProfile Wall Type when a new post is made

NewReplyNotificationUserProfile.Body, NewReplyNotificationUserProfile.Subject -> Used for the UserProfile Wall Type when a reply is made

NewPostNotificationCustom.Body, NewPostNotificationCustom.Subject -> Used for the Custom Wall Type when a new post is made

NewReplyNotificationCustom.Body, NewReplyNotificationCustom.Subject -> Used for the Custom Wall Type when a reply is made

and the following tokens can be used:

[WallPost:PostID]
[WallPost:RelatedID]
[WallPost:PostText]
[WallPost:Subject]
[WallPost:ParentPostID]
[WallPost:CreatedDate]
[WallPost:ChangedDate]
[WallPost:ChangedByUserID]
[WallPost:CreatedByUserID]

Do you know about the Email Header and Footer that is now making it's way into all Smart-Thinker modules? Read more here...