opt in email group lists

Please add opt in group lists to the email capabilities.  This would allow the members to opt in to an email group list that they would like to receive information on (junior tennis, social events, 2.5 clinics, etc).  If they feel they are receiving too much information they also have the ability to opt out.  This takes a HUGE amount of work off the admin's plate as they do not have to add or remove people from lists and allows the members to manage which information they wish to receive.  You can keep the current capabilities (which require the admin to add or remove) but certain information should be managed by the members themselves.  I had this with the last system I used and it was the best feature of the entire email system.