If you are looking for a way to increase the security of your Web site and to ensure that only things with flesh and bone log into your site, take a look at VidoopCaptcha, freeware that the Vidoop has offered to integrate with the most diverse web technologies.
We use it in php, plugin for WordPress, Drupal platform… several alternatives to prevent automated programs from taking control of our applications.
The result is similar to what we see in the image above. Instead of asking for letters asks users to identify pictures, being a much more difficult task for a robot with bad intentions