The referred leads are presold - because trust and confidence exist, at least to some degree. One of the best ways to get more leads is to focus on those who send you referrals already and to encourage them to do it more often. Most business people provide a referral reward or even some kind of fee to people helping them to obtain a lead that ends with a sale. Additionally some make it a standard practice to refer the source to their own potential clients when the opportunity arises.
Some people have even different rewards for different types of leads.
One thing is to mention your name - another is to insist that prospect contacts you. You will be really surprised with the mileage you get from those little gifts when you begin to invest in the business through referrals and follow up not only on leads but also your referral sources. It might become too expensive and too overwhelming to send a box of chocolates to everyone who refers your site to a friend - you might want to set up some reward system through autoresponder or downloadable file. It might a movie ticket or just a thank you note. It might be a gift certificate or more elaborate gift - depending on the type of your business and the potential value of a sale.