Customise the Drop Down Menu for the "Hear about Us" Field
Go to Admin > General Details > Hear About Us
When creating an event you have the option to enter how the customer 'heard about you'. You can now add relevant lead sources, these will appear in the 'Hear About Us' drop-down field. For example Word of Mouth, Repeat Customer or Promotion.
In the reporting area, a report can be generated for 'Hear About Us'.