Each mailbox has basic anti-spam filtering using a variety of different configurations, which are constantly monitored and updated according to the latest spam threats. These system wide filters are auto-learning and are always adjusting themselves to become more efficient at catching spam.
Every email received is stamped with several headers indicating the probability of the email being spam. Depending on your email service from us, our servers may move emails with a high level of spam likelihood into your JUNK/JUNK EMAIL box automatically. Mailbox users may also filter emails based on these headers to further reduce the spam in their mail inbox.