This happens way too often... The page is served over http and asks you to install it's addon. The addon is not verified. The addon is downloaded from "http://convergence.io/releases/firefox/convergence-current.x....

What's the point of providing such service if anyone capturing your internet traffic can change it in flight to a "return True" equivalent?

Edit: tried https... come on, they're not even trying: "The certificate is only valid for the following names: whispersystems.org , www.whispersystems.org"