When a user does not wish to receive notifications or messages, they can make themselves Unavailable. Unavailable users cannot be added to any new Discussions, but will receive notifications and messages on all current Active Discussions. Users remain Unavailable until they change their profile setting.

 Select your name, in the upper right, followed by My Account.

  Select Contact info, from the left panel menu.

 Uncheck the Available? Box.

Unavailable users are marked with aand may not be added to Discussions.

Follow the same steps to change profile setting to Available