Newbie - I want to trigger an action when a user creates / updates a profile I would like to trigger an action when a user creates or updates a profile.

What classes should I look for?

I search for the documentation but I didn't understand it much. Can you point me to the right direction?

Thanks a lot
You can use the Rules module for that.

http://drupal.org/project/rules

Create a new triggered rule and set it to fire on event "User account has been created" or "User account has been updated."  If you're using Content Profile, you'd set the event to be "after saving new content" or "after updating new content" and specify the node type was whatever you're using for content profiles.