A new rule by MasterCard could crimp online commerce by stopping merchants from accepting credit card payments through third parties, such as the popular PayPal, USA TODAY has learned. Unless a settlement is reached, on May 1 Internet merchants and other mom-and-pop firms that rely on third-party billing could miss out on sales via the USA's No. 2 online credit card. And MasterCard holders could have a harder time using their cards at many sites that use PayPal and similar services, says Gartner analyst Avivah Litan.

"The TelePay consortium, which comprises Systems@Work, Gemplus Technologies, Mobile e-Services Bazaar of HP, VISA International and Suntec City, will be working with 35 more merchants, bringing the number to 50, during this trial period."

See also the company's web site.