QuickTopic

QuickTopic (http://quicktopic.com/) is a website that provides individual, private message threads. It has become a common way of handling private communications in games because adding someone to the group is as easy as giving them a link to the thread, and everyone can participate without the hassle of sending PMs to several players. Some mods go so far as to make a thread for each group that can communicate outside of the normal game thread and simply provide a link in each Role PM.