Automatically create a Drupal node when a user registers

Sometimes projects come up that have requirements that cannot be solved with an out-of-the-box Drupal install. A project I worked on some time ago required that I store a node every time a user registered for an account. The details of the project are a little fuzzy for me now, so I'll just skip right to the example.

<?php
function mymodule_user($op, &$edit, &$account, $category = NULL){
  switch($op){
    case 'insert':
      // Automatically create the note settings (content profile) node for this new user
      $newnode = new stdClass();
      $newnode->title = "Note settings user {$account->uid}";
      $newnode->uid = $account->uid;
      $newnode->type = 'note_settings';
      $newnode->status = 1;
      $newnode = node_submit($newnode);
      node_save($newnode);
      break; //insert
  }
}
?>

This example shows how simple it is to programmatically create a node, and also shows the proper way to hook into the user system.