American Express (s axp), the company well known for overpriced charge cards, is buying Ted Leonsis and Steve Case’s Revolution Money for $300 million. Leonsis shared this information on his blog. Amex wants to use Revolution Money to build a next-generation offering. Revolution Money has some kind of a next-generation payments technology that brings together offline and online worlds; it’s part of the Revolution group of companies floated by Steve Case. No one I know has either seen it or actually uses it. If there is one company that is going to do offline-online payments, that will be PayPal (s ebay).