Limit amount of content creation per anonymous user
You could do it custom with hook_node_access and the Flood API.

e.g:

/**
 * Implements hook_node_access
 */
function MY_MODULE_node_access($node, $op, $account) {

    // Get node type, can be string or node object
    $type = is_string($node) ? $node : $node-&gt;type;
    if ($type == 'type_of_interest') {
      // Check flood limit for anon users node creation
      if ($op == 'create' &amp;&amp; user_is_anonymous()) {
        // Ensure checked only once per page request, node/add path only
        $access_checked = &amp;drupal_static(__FUNCTION__);
        if(empty($access_checked) &amp;&amp; arg(0) == 'node' &amp;&amp; arg(1) == 'add') {
          // Record the access check for drupal_static
          $access_checked = TRUE;
          // Check create_node limit of 2 per 12 hours
          // Note, you could make the threshold and window config variables.
          if(!flood_is_allowed('create_node', 2, 43200)){
            drupal_set_message(t('There is a node creation limit of 2 nodes per 12 hours. Please try again later.'), 'error');
            return NODE_ACCESS_DENY;
          }else{
            // Register the node create event to test against for 48 hours
            // Note, you could move this somewhere else to ensure the node is actually saved, e.g hook_node_insert
            flood_register_event('create_node', 172800);
          }
        }
      }
    }

  return NODE_ACCESS_IGNORE;

}