Twitter Begins Testing a ‘Buy’ Button for Instant Purchases by Its Users - NYTimes.com

Lots of Twitter "experimenting" lately; e.g., also see Twitter CFO hints at big changes to how your timeline works (Engadget)

"The test comes as competition in the world of mobile e-commerce intensifies. Apple is expected to unveil a new phone-based payment system on Tuesday as part of its latest update to the iPhone. And Facebook, Twitter’s biggest rival, began testing a “buy” button on its service in July. Social networks, including Pinterest, a sort of visual wish book, see e-commerce as a potentially huge moneymaker. All of them are experimenting with ways to make it easier to buy directly from their sites, but so far none have introduced purchase technology on a wide scale."

Twitter Begins Testing a ‘Buy’ Button for Instant Purchases by Its Users - NYTimes.com