A mail filter allows you to FILTER OUT any unwanted mail from members who don't meet your criteria. To activate your mail filter select the criteria of the people whose mail you are interested in receiving and set your mail filter Settings to "ON". Any mail sent from members who don't meet your criteria will be automatically FILTERED OUT into your filtered mail box. You should still periodically check your filtered mail to see if you have any wanted mail from people who meet part of your criteria.