What you suggest actually was something done when Steemit first launched. I never understood why that seemed to die out. Here is a link to my introduce yourself post. I think this would be an excellent idea!
Perhaps a whole new user community could be launched with different post criteria. Almost like an achievement system. For instance, post in the introduceyourself category in the community with an introduce yourself article, post in the 10thpost category in the community when you hit your 10th post, post in the 50followers category when you hit 50 followers, post in the firstpayout category when you get your first payout, etc... Stuff like that to demonstrate progress and growth amongst new users. Just a thought.
RE: 100 DAYS OF STEEM : Day 10 - A Steem Mentoring System