The newest type is the incoming lead generation, which depends on people who find you and plan to contact you. One example is someone who is looking for a car, visits your blog and picks a model, and then opts for a list of emails for future offers and promotions.  

Outbound lead generation is the other, This is where your customers are still unfamiliar with you and your product but you reached out to them either through emails or phone calls to create a demand or hunger via soft selling for your product or services. The classic example is a phone caller or an email from a business that you have not signed up to get.  

Lead generation seeks to provide people an opportunity to learn more about themselves and your industry and to give them a chance to learn better about you and your approach.