Showing popup after user registration using the "Popup message" module How do I show a popup to a user after he/she has registered, using the Popup message module?
Not with Popup message but this will work:

Install Rules, then create a rule with the following settings:


React on event: After saving a new user account 
Actions: Show a message on the site (your message)


Drupal will show your message as a system message.