gelgels·14 ปีที่แล้ว·discussI don't know her HN username, but Amy Zhou (Princeton) and I think one of her team members won last year and was present this year.
gelgels·14 ปีที่แล้ว·discussSome credit cards have "virtual numbers" that you can use for shopping online. You set the limit that can be charged on the numbers and you're notified if someone charges over the limit to the virtual number. (citi credit cards)