This evening at a Wall Street Journal technology conference, Apple CEO Tim Cook said that in its first 72 hours, Apple Pay activated 1 million cards. That figure indicates that Apple Pay is picking up traction outside of the technology, early-adopter set. Apple Pay competes with rival offerings from Google, among others, alongside traditional payment methods. Paying for goods with your smartphone, still nascent in the Western market, could grow quickly: Given smartphone penetration in the United States and other developed nations where this sort of transaction system remains new, Apple has the potential to quickly scale its new product. The possible revenue for Apple is not trivial. The company picks up 0.15 percent of transactions, or 15 cents per $100 dollars in payments. That isn’t much on a per-transaction basis, but it could quickly add up for the company worth more than $600 billion. If its smartphone user base adopts its Pay technology, the product could bring in fresh top line for Apple, a company looking for a new hit. Of course, 1 million cards is a fraction of the total number of saved credit cards that Apple has via its iTunes and long-standing app businesses, implying that it could enjoy continued quick growth. How large its payment volume will grow in the meat space remains to be seen.