Hotmail users emailed friends and family. Friends and family saw that message at the bottom and signed up for their own free email account. Then they started emailing their friends and family. And so it went... as Hotmail exploded from 500,000 users in 1996 to 12 MILLION users just six months later. Today there are over 500 Million users that did not come from a multi-million dollar advertising budget. All of them came from the powerful new concept called "Viral Marketing".
