Chances are, with the way lead brokers work, you probably have.. You know, the purpose of any business is to increase revenue and decrease expenses... In the sales lead business, once you sell a lead to a broker, they may sell it to other brokers, and then you end up with a person getting harrassed and no longer interested in what they inquired about to begin with... this is frustrating for the end consumers as well as businesses that pay big bucks sometimes for what could be useless information... basically, blockchain would mean more ethical treatment of people's information and eliminate the demand for brokers.