hotmail reputation service

Hotmail Reputation Service

Don't use a major national free email provider as your primary address - spammers will often target common usernames on widely-used email domains like hotmail, yahoo, aol, msn, etc.
An e-mail address obtained from a free e-mail provider (such as Hotmail, Google, Yahoo, etc.
Hotmail has a user reporting feature, the moment hotmail users spot a spam email, they are encouraged to report it back to hotmail.
Hotmail feeds this data back to microsoft which maintains the database for spammers.