Great question and we would like this for the same use case. 

From what I’ve heard, they’re planning to (build the ability to) allow for widgets on the home page to be customized based on a persona (hopefully user role and/or rank). What that would mean is that you could have someone’s initial role/rank be one thing at the outset, and after a certain criteria (age of the account) change them to the next one…. and then set the welcome article as a featured topic widget that only shows to that initial rank. 

But we have to wait until this is built. 

Although technically you could put something like that in a community category or KB category that is permissioned for only a certain user type. Then take the same approach of aging them out of that role/rank. That way, if you put it in a featured topic widget on your home page, they won’t see it once they no longer have permission to see it. (But you lose the ability for them to access it later if they bookmark it, search for it, etc)

Finally, a best practice @Shane1 shared with us: Send the welcome article to them in automated private message by creating that initial rank. This ensures each user has it hand-delivered to them in a highly visible way (notification, system email, etc). 

Bonus tactic: for a time, we had featured our “Getting Started” onboarding article in a sidebar widget so that it shows prominently on the side bar of most forums and topics.