Rather than waste time and money driving to a brick-and-mortar store, many shoppers prefer to make purchases with a few keystrokes and a click or two of a mouse. To keep up with customers’ shopping behaviors—and the widespread demand among consumers for convenience—credit card companies are beginning to target a new area of commerce: social networks.

Some 16 percent of online adults use Twitter, according to a 2012 report by Pew Research Center’s Internet & American Life Project, yet social platforms offer a region of e-commerce that’s been largely untapped by credit card companies. American Express is one company that’s encouraging shopping on social networks; it launched a program in February that enables its customers to buy products directly on Twitter.

The service—available to those with Amex credit cards and a public Twitter account (prepaid and corporate cards are exempt)—is a simple process. Members sync their credit card to their Twitter account, then they can tweet special hashtags for products they wish to purchase. For example, last month American Express offered $25 Amex gift cards for $15. By using #BuyAmexGiftCard25 in a tweet, customers received a reply tweet from the @AmexSync account containing a confirmation hashtag. The customers had to tweet that hashtag within 15 minutes to purchase the product, which was subsequently shipped to their billing address.

Click here for more on the tweet-to-buy business model and whether experts think it will take off.