Some snippets from the README.txt

The Field Actions module combines the power of Drupal actions with the data in
CCK nodes to create new ways of working with your nodes in Drupal. This module
enables action enabled modules (such as workflow.module) to reach into your
nodes, pull out information, and use it appropriately. This leads to more reuse
of data throughout your site, and easier creation of behavior for
non-programmers and programmers alike.

TO DO:

1. Add actions for other CCK fields. Some plans include:
 - Apply action to node referenced by field - apply an action to every node
listed in a node reference field. Additionally, do the inverse, apply action to
every node that references a the acted on node from a given field.
 - GET or POST data from/to a given web url field
 - Combine fields to work in tandem

2. Define a field that contains a UI for invoking actions on certain events
(i.e. submit/save, new revision, cron interval, etc).