BBM use a PIN based system instead of phone numbers or emails to identify users. This PIN, along with its QR code are generated the user sign-up to BBM
To get the PIN and barcode (For iOS and Android):
Open the BBM app.
Click on Scan Barcode.
Your PIN and QR code are displayed in this section:
To share your PIN.
Tap on Copy PIN and paste it in a text message.
Tap on Share My PIN to share your PIN on social networks.