For the first week a new post is published a NEW! badge will show at the beginning of your post byline, then disappear to allow your future new posts to take the spotlight.
To add this to your own website, login to MD > Site Design > Content > Loop and begin customizing the blog display loops with different templates and settings, including the Byline editor with badge settings:
To take this further, you can edit the byline of archives template and single post templates with the wider lense of options easily available in MD Site Design:
So you can have the right byline across all different kinds of categories, posts, and pages: