Junk email costs millions of dollars every year in wasted time, bandwidth, and resources.
Much of it advertises adult material but it is sent to adults and children indiscriminately. It is hard to control and hard to filter. Stamplets offers the chance to change the situation. At the moment it costs a spammer a few dollars to send a message to millions of victims, but the costs to the ISPs and the ISP's customers are huge. Stamplets redresses the balance by forcing spammers to pay.