Twitter Cards with Metatag module not working I've got the metatag module installed and enabled. I've also enabled the MetaTag: Twitter Cards sub-module so that it will render meta tags for twitter cards, but I'm not seeing any twitter: metatags in the head at all. 

Here is a page on my site:

http://www.inadaydevelopment.com/app/ios/10bii-financial-calculator

Here is the export of the Node configuration, I believe the only thing I changed is that I set a creator value for my twitter account:

$config = new stdClass();
$config->disabled = FALSE; /* Edit this to true to make a default config disabled initially */
$config->api_version = 1;
$config->cid = '1';
$config->instance = 'node';
$config->config = array(
  'title' => array(
    'value' => '[node:title] | [site:name]',
  ),
  'description' => array(
    'value' => '[node:summary]',
  ),
  'og:title' => array(
    'value' => '[node:title]',
  ),
  'og:description' => array(
    'value' => '[node:summary]',
  ),
  'twitter:creator' => array(
    'value' => '@inadaydev',
  ),
  'twitter:title' => array(
    'value' => '[node:title]',
  ),
  'twitter:description' => array(
    'value' => '[node:summary]',
  ),
);


I created a new default metatag for content type App, here is the export:

$config = new stdClass();
$config->disabled = FALSE; /* Edit this to true to make a default config disabled initially */
$config->api_version = 1;
$config->cid = '2';
$config->instance = 'node:app';
$config->config = array(
  'twitter:image' => array(
    'value' => '[node:field_phone_screenshots]',
  ),
);


However, none of the twitter:card meta tags show up at all... what am I doing wrong?
If you´re using the 7.x-1.0-Beta4 version of metatag module (which is the most recent one at the time of writing this answer), you may want to apply the following patch:

http://drupal.org/node/1846978#comment-6764558

(for Unix-like systems only) For applying the patch, just go to a terminal, change the working directory to the directory of the metatag module and try this:

curl http://drupal.org/files/metatag-fix_theme_hook_mismatch-1846978-0.patch | patch -p1