The mobile payments/digital wallet drama now unfolding is fascinating for three reasons: First, paying with your mobile phone is the most fundamental shift in retail commerce since the credit card was invented 60 years ago. Second, mobile payments are just starting to be adopted by consumers. Third, the field is wide-open.

The mobile payments/digital wallet drama now unfolding is fascinating for three reasons: First, paying with your mobile phone is the most fundamental shift in retail commerce since the credit card was invented 60 years ago. Second, mobile payments are just starting to be adopted by consumers. Third, the field is wide-open. Leading companies from Silicon Valley to Wall Street, not to mention retail giants and telecom titans, are furiously jockeying for position.

Each major player brings a competitive advantage to this showdown, but so far not one has been able to strike more than a glancing blow. That changed Wednesday, with PayPal’s announcement of a partnership with financial services giant Discover to enable transactions at more than seven million retail locations nationwide. For online payments pioneer PayPal, this is an ambitious step to move offline into bricks-and-mortar transactions at the cash register.

“This is not technology for technology’s sake,” says PayPal spokesman Anuj Nayar. “This is about removing friction from the retail process and giving consumers more options.”