I'm gonna try and channel the average user's priorities when selecting their messaging app: 1. Are the people I chat with on there? 2. Is it free? 3. Do I ha

I'm gonna try and channel the average user's priorities when selecting their messaging app: 1. Are the people I chat with on there? 2. Is it free? 3. Do I have to install something? 4. Is it easy to use/sign up? 5. Does it have the bells and whistles I want? .. X. What does end to end encryption mean?