Facebook 上的行動電話號碼除了被拿來當作 2FA 的備案外，也被強制分享。更糟的是還被拿來當作廣告的條件：
For years Facebook claimed the adding a phone number for 2FA was only for security. Now it can be searched and there's no way to disable that. pic.twitter.com/zpYhuwADMS
— Jeremy Burge ?? (@jeremyburge) March 1, 2019
This is so crazy: even if you deliberately don't include your mobile number in your Facebook profile, they'll harvest it when you use it for two-factor authentication, and let advertisers target you with it. https://t.co/0TIr0zsJOt pic.twitter.com/TigHlGR2zF
— Tom Gara (@tomgara) September 26, 2018
手機號碼拔掉之後完全沒有2FA，連FB app裡面的TOTP都不見了