Is it possible to show notification in MacOSX or Safari?
I dont know what the Wordpress module does.

But for the server running the website you can send notifications to the OS using Drush Notify (built into Drush version 6).

From the readme it has a few example functions:


drush_notify_send(): Send a message to notifications center and audio.
drush_notify_send_text(): Send a message to notification center.
drush_notify_send_audio(): Send a message to audio system.