The idea has been on the drawing board for more than a year, but 'MEGAchat' is good to go.
It is basically just audio and video calls right now but text chat and video conferencing are on the way. After creating a Mega account, you simply log in via the web and hit the Conversations icon on the left-hand side. Contacts will need a Mega account and after making a few calls you'll see a basic chat history on the right-hand side.
What is important is that it is free and promises better protection than alternatives such as Skype and Google Hangouts. Of course, the US will say that it will become the communications tool of choice for terrorists and criminals because they can’t crack it. It will not endear Dotcom to them much, but then again they do not think very highly of him already.