The routing between the acquiring bank and the issuing bank, which is what MasterCard does, we typically call that "switching the transaction." That happens in a 140 milliseconds. An eye blink takes about 400 milliseconds. So about three transactions go through every time you blink your eyes.

At the other end of the network, as we switch to the issuer, they take it and look at your account. They'll look at things like how much room do you still have on your card. If it's a debit card: Is your debit account OK to take this [charge]. We have fraud tools that get involved to look at it to try to make sure it is not a fraudulent transaction.

And then they pass back the approval to us, and we give it back to acquirer, who gives it back to the merchant. All that happens in just a few seconds -- just a tremendous amount of processing.

How big will contactless payment become?

Reeg: It's actually rolled out now. You'll see terminals at different places and devices, like in movie theaters, and fast-food restaurants that accept PayPass.

How have you prepared for this?

Reeg: One of the things that MasterCard did really well a few years ago is that we rewrote our core processing systems. We had some really good technology architects who did a great job thinking about what we need to have to support the future. They came up with this concept: Our systems really needed to be agnostic as far as it went to the point of interaction.

So whether a transaction is originated via a contactless card, a cell phone, the Internet or just a regular swipe, it shouldn't matter as long as we build the system that is open and can accept the transaction coming from any device. We invested about $160 million in that rewrite, and it has really paid off well, now that we see more and more different kinds of devices that start a transaction.

How large is MasterCard's data warehouse?

Reeg: The ultimate goal for MasterCard IT is how do we leverage technology to drive business. The tenet is: We should look to see how we can make every transaction more valuable to all those four stakeholders in our four-party model. The data warehouse is a key component of that whole strategy. Look at the warehouse itself: There's obviously a wealth of data just from the sheer volume of transactions that are being processed, and we know that we can take that data and help our customers better market to their own card holders or better serve their own merchants.

There's over 100 Terabytes of transaction data in our warehouse now. We really believe there's a capability that we're going to have 1.8 Petabytes as this continues to mushroom.

Fraud prevention is a hot topic these days. What's your role in that?

Reeg: We build specific tools for our banks to use to help augment their own fraud-prevention services. It's funny, the last time I was in Europe my personal card data was compromised. My bank called me before I knew anything about it and told me they were seeing unusual activity. Again, when you can leverage the data of a 100 Terabyte data warehouse, and build neural network type models based on spending patterns and what merchants I typically go to and what places I usually visit and all that, then there's s wealth of data that our customers can use and we can give them tools to help use to help prevent fraud.

It's a constant, constant battle, and something we have to be very vigilant about because the bad guys out there are just as determined to use things the wrong way.

How can data warehouses and large infrastructure operations like yours be green?

Reeg: We actually believe there's a financial benefit from that as well just in terms of energy consumption. We custom build our data centers, and we had some opportunities to put in, for example, extra high ceilings to disperse some heat. We're heavily into virtualization so that we can reduce the numbers of footprints.

We operate in 210 countries around the world, with 25,000 different financial institutions. In doing that we leverage a global workforce. So part of that is: if I have programmers in Asia, they're using the same server that my programmers in U.S. are using, but at different times of the day. So I can get better usage of a server by having a global workforce as opposed to having to buy multiple servers, if everybody's in the same location.

How critical is IT to MasterCard's success?

Reeg: This has to be one of the best IT jobs in the world. A lot of companies struggle with: Are the IT goals aligned with the business goals? There's no difference here. Our IT goals are the business goals and unless we're absolutely linked, MasterCard doesn't function as effectively as it could.

Do you feel extra pressure because of that?

Reeg: I think it's just the business we are in. The difference between the president's role and the CTO role [I previously had] is that you have to be thinking from a business standpoint all the time. How does any change we make help make the business be better for our customers, cardholders and merchants. How do we leverage technology to be better for all the stakeholders? It really drives the business.