Feb 23rd, 2013
A must learn module: "This module augments Views by allowing bulk operations to be executed on the displayed rows. It does so by showing a checkbox in front of each row, and adding a select box containing operations that can be applied. Drupal Core or Rules actions can be used."
To add a new operation programmatically, see the VBO documentaion page: https://www.drupal.org/node/2052067