D7 email formatter to hide address

oog_email_formatter.info

name = Oog Email Formatter
description = Replaces actual email address with the word "email"
core = 7.x

oog_email_formatter.module

<?php

/**
 * Implements hook_field_formatter_info().
 *
 */
function oog_email_formatter_field_formatter_info() {
  // Add a setting to a formatter type.
  $formats = array(
    'email_custom' => array(
      'label' => t('Email Custom'),
      'description' => t('Display the email address as custom format.'),
      'field types' => array('email'),
    ),
  );
    return $formats;
}

/**
 * Implements hook_field_formatter_view().
 */
function oog_email_formatter_field_formatter_view($entity_type, $entity, $field, $instance, $langcode, $items, $display) {
  $element = array();
  switch ($display['type']) {
    case 'email_custom':
      foreach ($items as $delta => $item) {
        $output = l("Email", 'mailto:' . $item['email']);
        $element[$delta] = array('#markup' => $output);
      }
      break;
  }
  return $element;
}