The system, unveiled at the firm's annual PayPal X Innovate conference, lets users pay for virtual goods and content in as little as two clicks, without having to leave a publisher's game, news, music, video or media site.

Facebook has agreed to integrate the technology in its site and is joined by Autosport.com, FT.com, GigaOM, Justin.tv, Ooyala, Plimus, Tagged, Tyler Projects and Ustream.

Mary Beth Christie, head, product management, FT.com, says: "Our readers want their news on demand, whether they're on a laptop, a mobile phone or a tablet. PayPal helps us provide the experience our customers expect, along with flexibility to experiment with payment mechanisms for subscriptions. This gives our customers the flexibility to pay for what they want, when they want."

PayPal has also introduced an online checkout system for physical goods that does not require the customers to leave a merchant's app or Web site. The system, which has been adopted by FundRazr and Payvment, means users can create an account, view payments details, choose a shipping address and approve the transaction without being redirected to PayPal.

Bill.com, CreditKarma, Expensify, Freshbooks, Shipwire and Zuora have all signed up to another initiative which lets developers embed their applications directly in the PayPal Web site.

Meanwhile, Discover has teamed with the eBay unit, tapping its new Adaptive Payments APIs to offer card members person-to-person payments. The Money Messenger system lets customers send money to another person via Discover.com or a smart phone using only the recipient's e-mail address or mobile number.

Another financial services firm, USAA Bank, is also using PayPal technology for a P2P payment system that only requires e-mail addresses or phone numbers. This is expected to go live next year.

On mobile initiatives, in addition to the previously announced VeriFone integration, a new PayPal iPhone app is being launched with location-based features and there are also new functionality and enhancements to the Mobile Payments Library.

Osama Bedier, VP, platform, mobile and new ventures, PayPal, says: "The convergence of mobile, social networking, and location-based technology is creating tremendous opportunity for developers today. It's like the gold rush of the dot-com era, only bigger and smarter."