Is there an easy way in Plone to get email notifications when new users join the portal?
You can also just have login_next traverse to a Controller Python Script (you'll fine other similar ones in the /plone_login area of the core Plone product that end with the extension '.cpy') that you write that sends the email (perhaps notifyMangersUponLogin ) rather than it's default of traversing to login_success.
Then, have your CPT script traverse to login_success to continue the sript/page MVC flow that Plone ships with, if that's what you want.
To leverage Controller Page Templates (.cpt files)/Scripts (.cpy files), it's key to not only copy the custom version of login_next.cpy to your custom product's skin path, but also the login.cpy.metadata file that specifies the success/failure actions of the MVC page/script logic flow.
With Plone 4.0.2, you'll find the Plone login-related scripts/templates under a path such as:
/buildout-cache/eggs/plone-4.0.2-py2.6.egg/Products/CMFPlone/skins/plone_login
relative to your buildout structure.
I want to get email notifications to the portal email address whenever a new user joins the portal.
My guess is that I should code a new product to do that.
Does such product already exist (for Plone 4)?
I checked content rules, but AFAICT it could work only if I made the users contentish themselves with something like membrane/remember, but for my requirements that would be overkill.