As a professional email marketer, I will tell you some things on list and leads generation. Getting list and leads is something you need to build up your business. I know you will ask why. The reason why is that it will give you some privilege like having access to your customer or subscriber in other to send them Campaign about maybe new product, giving them Newsletter it can be Sales/Pitch or Informative Newsletter, or you want to pass some information on your business or site to them and will let them know more on this. Lists is Collection of email addresses into your database or into CSV format. Leads is in form of collecting full details about the subscribers and saving to your database.