If you have ever spent your time calling and emailing leads you bought from a list broker then you know how difficult that can be. Now compare that to having a list of people who know you and look forward to hearing from you. For more information go to www.build-huge-list.com. This is what opt in list is. People who have agreed to receive email from you. When they fill out on online form and hit the submit button they are opting in. When they click on the link in the first email they receive they are now a double opt in lead.