>>Retric+(OP)
The lack of a social network is why I settled on Signal. Before using Signal I tried Telegram, which requires a phone number and if they recognize your number in any of their user's contact list (which many people seem happy to allow access to), they'll send them a notification telling them their contact has joined. I got a nasty message within 10 minutes of making an account from a woman accusing me of pretending to be her deceased father. I had inherited his phone number a decade prior, and it told her I had made an account. I was so shocked they not only allowed, but encouraged such behavior that I deleted it promptly and swore I'd never use it again.