#OPSEC365 236/365
Messaging apps harvest phone numbers from your contacts to build user databases.
When Signal, WhatsApp, or Telegram checks which of your contacts use the service, they're uploading phone numbers to their servers. Even if your contacts never joined, their numbers exist in the platform's database because you uploaded your address book.
Every contact you upload gives that platform the phone number of someone who never agreed to be in their database.
#OPSEC365
