Users that can add other users in drupal 7 Scenario is as follows: admin adds users (coordinators). Coordinators should be able to add another type of users (editors) which can create content. What is the best solution to this scenario? I don't want any of the users assign roles to other users. Coordinator should be able to add only one, defined type of user.
There's a module for that: Administer Users by Role.


  This module allows site builders to set up fine-grained permissions for allowing users to edit and delete other users — more specific than Drupal Core's all-or-nothing 'administer users' permission. It also provides and enforces a 'create users' permission.
  
  To use this module:
  
  
  Create a role for the users who you'd like to be able to create/edit/delete other users
  Give that new role the 'administer users' permission and give it the desired Administer Users by Role permissions
  


I'm using it exactly for the same purpose you described.