Android/iOS: You might have heard that Facebook is buying WhatsApp. While the move shouldn't affect users in the short term, some people are uneasy about a company with a spotty security history being bought by a company with a spotty privacy history. If you're in that group, Telegram might be of interest to you.
Telegram is a messaging app that's remarkably similar to WhatsApp. However, the company behind it claims that the app is built from the ground up with security in mind. Messages are encrypted (and there's even a bounty for anyone who can crack it), servers are distributed throughout several countries, and you can even enable self-destructing messages.
As we've mentioned time and time again, just because an app says it's secure doesn't mean that your messages can't be copied or saved. Even the notable Snapchat isn't safe. However, starting from a stronger base is always better than taking the chance on a riskier service. If you're concerned about WhatsApp's security, Telegram may be worth a look.