The Anti-Spam Solution Used With Respect to over 700 Million Email Accounts.

Our patented Sender Accreditation technology, Email Self-Insurance®, has made it economically prohibitive for commercial emailers to send spam without putting undue burden on their sending of legitimate emails. Commercial email senders, who are not yet well-known to be trustworthy, make a substantial pre-payment in order to send accredited emails over a particular time period. But the accreditation, and the ability to send such emails, is withdrawn when recipients complain, and the infringing senders are not reimbursed for the unused portion of their contract. Because the cost of paying for, and then losing, the use of their privileged status exceeds the short-term financial returns of sending spam, emailers are deterred from sending unwanted email. In this way, trustworthy commercial email senders get to build a track record for having a legitimate opt-in list of email recipients, thus eventually obviating the need for further pre-payments or deposits. 
The solution has been licensed with respect to well over 700 million email accounts, and Microsoft has publicly acknowledged that it is the company's leading solution to spam.