It really depends on what the system needs and how you are reusing functionality. Creating a user on the front end of the site with a new user sign up makes sen

It really depends on what the system needs and how you are reusing functionality. Creating a user on the front end of the site with a new user sign up makes sense to send an email, but if you have a back-end admin area, creating a new user there probably wouldn't be a good idea to send out an email in many cases. In short, use your head. There is nothing wrong with breaking out this functionality into two actions.