Whether they’re named or not, sometimes you just don’t want to be bothered by the incessant back-and-forth of a group message. In Yosemite you won’t have to anymore. Inside the Details window are two ways to put a stop to the distractions: Turn on Do Not Disturb to stop getting notifications every time someone has a reply, or leave the conversation entirely. And like everything else, whatever you decide will be reflected on all of your devices. (MacLife)