How secure are our messaging tools and apps--iMessage and FaceTime and Skype and even security-focused apps like CryptoCat? ProPublica and the Electronic Frontier Foundation (EFF) took a deep dive on the most popular messaging apps to reveal how safe they keep our messages.
On ProPublica's site, you'll see a simple ranking of the best secure messaging tools, across the seven measurements, which evaluate whether or not the app encrypts the message in transit (most do), encrypts it so the provider can't read it (not all, but more than half do), and whether your previous messages are secure if your security keys are stolen (for less than half of the tools, no).
Of the apps they tested, CrytoCat, Silent Text, Silent Phone, TextSecure, Signal/RedPhone, and ChatSecure + Orbot were the only ones that scored the top marks across all categories. These are the ones to consider if you're concerned about the privacy of your messages.