Phone SMS Verification on Registration
New users must submit a valid phone number and verify it by receiving an SMS code. The phone number will be usable for just 1 account, thus preventing multi-accounts from being created by the same person easily. The SMS service relies on a 3rd party which charges around 0.08$ per SMS. To prevent any exploits from users, each IP is limited to maximum 5 verification attempts per 15 minutes. Other security methods that prevent phone number phishing/guessing are also in place.