1. New Authors - Looks for authors who posted their first blogpost in the last 24 hours.
2. Productive Steemians - Looks into all users accounts, retrieves the first n-th users in descending order sorted by the number of their posts (blogposts and comments).
3. Steemlytics - Looks for the most voted authors by high-power users (in the course of the last 7 days).
4. Curie - Looks for the blocks in the timeframe 6 hours ago - 20 hours ago, and gets links for blogpost from authors with < 60 reputation, < 3000 steem power, and < 100 followers.
To learn more about the code behind the steem blockchain and steemit go to the official github. To start blogging on steemit (the social platform that rewards all its users) go to the website.