Came across OneOne this weekend and was a bit skeptical. The Next Web review said it has an advantage over Telegram which I've been using for months. What I like is that there is no login or authentication of any kind. It doesn't support groups but for one to one privacy I can't think of anything less traceable. Has anyone else used it? This is the article on TNW how I discovered it. http://thenextweb.com/apps/2014/11/18/oneone/