• Telegram has a phone number-based authentication method, although you can use it without sharing any of your contacts. Telegram will continue to allow you to add people, and others will be able to discover you by searching for your username.
• Telegram syncs your contacts to its servers by default. You'll receive an email notification whenever a new contact joins. Your contact will also be aware of your Telegram usage. You can disable the Contact Sync option if you want to keep your identity hidden. Telegram will continue to function correctly as before. Users can be added by their username or by creating a new contact in the Telegram client.
• Telegram has a phone number-based authentication method, although you can use it without sharing any of your contacts. Telegram will continue to allow you to add people, and others will be able to discover you by searching for your username.
• Telegram syncs your contacts to its servers by default. You'll receive an email notification whenever a new contact joins. Your contact will also be aware of your Telegram usage.
• You can disable the Contact Sync option if you want to keep your identity hidden. Telegram will continue to function correctly as before. Users can be added by their username or by creating a new contact in the Telegram client.

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