Send an e-mail to an administrator when a new user registers on a Drupal 7 site

10:13 benjamin-agaric: Drupal 7 - the simplest way to have an administrator e-mailed when a new user signs up? Can't find any core setting and no trigger does it either? Seems we should have a way to get this functionality short of Rules module... thoughs?
10:22 benjamin-agaric: Answer: it can be done through Drupal core- an advanced action simply has to be configured first at admin/config/system/actions/configure and then back to trigger configuration.
10:22 benjamin-agaric: So the remaining question is not about Drupal but about me: why did i have to look at the code to figure this out? :-P

in the context of making an e-mail to send to a user. The action is "send an e-mail". It has no idea about what the trigger might be, which affects the tokens that will be available, and there is no master list of placeholders available in the UI. So the administrator is pretty much flying blind.
10:50 benjamin-agaric: and the tokens [user:name] and [user:mail] were not converted.
10:51 benjamin-agaric: so for sending an e-mail when a new user signs up... yes, token is completely broken.

Issue filed, and patch provided:
No user account tokens are replaced for the user account created trigger
http://drupal.org/node/870868

Reference

Same problem in D6? Advanced Actions - Send email - Only global variables work - System Module

The action itself:
http://api.drupal.org/api/function/system_send_email_action/7

Token, expanded and improved, lives on in contrib:
http://drupal.org/project/token