Google+ s new Huddle function is a group messaging platform that allows Google+ friends who have the G+ application to communicate en masse Twitter-like. Starting a Huddle will send a text message to all your designated Huddle friends. If they haven t yet downloaded the application, they ll have to agree to the Terms of Service before partaking in the conversation. Beware, though: there s a fine line between huddling and spamming.
Source: https://threatpost.com/huddles-and-muddles/91843/