Maybe now (as Facebook is on a shopping spree, buying Whatsapp for $ 19B) is a good time to try to convince some more people of a better instant messaging service. I'd really like to see Threema being adapted more wideley, but hardly anyone I know is using it right now.
Come on folks, paying € 1,60 for a good, app that respects your privacy and a service without recurring costs is really not that bad of a deal. So go and grab it:
By the way: you don't need to give Threema your number or email address, yet you can do it if you want your friends to find you conveniently.
Threema uses end-to-end encryption, meaning your conversations can't even be read by Threema itself, as they only store your encrypted data and claim to not having access to your key. Of course, as with any proprietary software, there's no way to be totally sure there are no backdoors involved. From what I read about Threema I decided it's at least way more trustworthy than Whatsapp and/or Facebook.