For a smartphone user, a phone contact sharing app (such as Truecaller) may

• collect names and phone numbers of all contacts in the user’s address book; and

• use the collected numbers to provide (1) caller ID service to another app user when such other user receives a phone call or an SMS, (2) contact search function to another app user when such other user queries a specific phone number, or (3) call blocking services when another app user wishes to prevent spamming call or SMS or to receiving calls from a specified collected number.

Under the anti-spam regulations (Decree 90/2008),  a collected phone number may be considered as an “electronic address” (địa chỉ điện tử). This is because an electronic address is defined as the address used to receive or send data message through the information infrastructure. If a collected phone number is an electronic address, then the collection of phone numbers through a phone contact sharing app may be subject to the following restrictions of anti-spamming regulations:

• Decree 90/2008 prohibit the distribution of software that can collect electronic addresses. Phone number collection function in an app can be classified as a software that can collect electronic addresses; and

• Decree 90/2008 prohibits the exchanging and trading of lists of electronic addresses without the consent from the owners of such addresses. Users using phone contact sharing function may be classified as exchanging list of electronic addresses.