How is Drupal Planet realised? How is the Drupal Planet realised?
I found the Planet installation profile, but it seems to be dead (the Git instructions tab is empty).
Drupal planet is built upon the core aggregator module, blogs are required to set up a special feed (generally tagging it drupal-planet) to be imported in the list.

That should be pretty simple to reproduce: What is Planet Drupal and how do I get added?