Technically it doesn't have anything to do with "Jehovah's Witnesses". It's the work of the International Bible Students Association (ISBA) see: http://www.internationalbiblestudents.com
The International Bible Students Association still exist to this very day. They are active and hold conventions ... etc.
Here's an article examining why the IBSA are not Jehovah's Witnesses (and vice versa): http://www.friendsofjehovahswitnesses.com/2011/09/01/bible-students-are-not-jehovahs-witnesses/