Short answers, pulled from the story.
A debit card is a payment card that withdraws funds directly from the cardholder's bank account at the time of purchase. Unlike a credit card, which extends a line of credit that the cardholder repays later, a debit card requires the money to already be in the account and transfers it immediately to the merchant.
The three types are EFTPOS (online or PIN debit), which authorizes transactions electronically and withdraws funds immediately; offline debit (signature debit), which places a hold on the account but delays the actual withdrawal by a few days; and the Electronic Purse Card system, which stores value on the card chip itself without requiring a network connection.
Interac Direct Payment launched nationally in Canada in 1994. By 2001, more transactions in Canada were being completed with debit cards than with cash. Debit card use in Canada dates back further, with credit unions in Saskatchewan and Alberta introducing networked ATMs beginning in June 1977.
Prepaid debit cards carry several risks: if the card is lost and was not registered, the money on it is likely gone. If the provider experiences technical issues, the funds may be inaccessible. Some companies' payment systems do not accept prepaid cards, and some government-issued prepaid cards have been criticized for carrying higher-than-average fees including flat fees on every purchase.
The Dankort was introduced on the 1st of September 1983. By September 2008, four million cards had been issued. In 2007, the Danish operator Nets processed a record 4.5 million Dankort transactions in a single day, on the 21st of December.
Consumer protection varies significantly by country and network. Visa and Mastercard prohibit merchants from setting purchase size limits or adding surcharges. In India and Sweden, consumer protection is identical regardless of the network used. In France, banks are legally liable for card-not-present and copied-card fraud, shifting the financial risk away from cardholders. Singapore disables international card usage by default to prevent unauthorized foreign transactions.