To manage Prospect Assignment Emails and the sources the prospects were received from, hover over Settings, then click on Prospect Details.
When a prospect is created, there is an option to assign it to a specific employee to do the follow up. Here is where you have the ability to turn on and off the emails to the employee. If a prospect is created and then assigned to 'Anyone', and also the checkbox next to 'To Anyone' is checked, then all employees will receive an email that a prospect has been assigned to all of them.
If a prospect is created then assigned to a specific person, and the box next to 'To An Individual' is checked, then only that specific employee will receive an email that a prospect has been assigned to them.
Make sure to click save after you check or uncheck a box.
The bottom half of the page is the Prospect Sources. Here is where you can add or delete where the prospect came from (i.e. Groupon, Birthday Party, etc).