Comment by Psion7

They say the network communication is encrypted between end points but they don't say analysing is not being done prior to encryption on your end. What I mean is it is possible for the communication over the network to be encrypted between Bob and Alice but everything Bob writes to Alice could easily be used by WhatsApp/Facebook prior to being sent. They could even go as far as to encrypt it and just transmit your side of the conversation to their servers for later analysis.