Nearly a year after taking over as CEO of IBM, and a day after adding the chairman title, Ginni Rometty addressed what she's learned and where the company is focused going forward. (Hint: marketing.)

"Clients say, 'What's your strategy?' and I would say, 'Ask me what I believe first." That's a way more enduring answer,'" she said. Focusing on strategic beliefs allows IBM to agree on a few big arcs of change -- for example, the emerging era of cognitive computing -- and then let smart employees loose to try things and find opportunities. Then, "if you can align everyone around a couple of those it's an energizing and inclusive way to create a long-term strategy," she said. "[It's about] directional arcs."

Ms. Rometty said one of the most important elements of reinvention is making new markets. One of the latest markets the company trying to make when it comes to data and cognitive computing is in marketing.

"Big Data's one thing, but you'll never be able to get through it all," she said, explaining why IBM is excited about the rise of cognitive computing -- essentially machines whose ability to learn can help sort through massive reams of data and figure out what's right and wrong on the fly. "Everybody's job -- the front office, CMO, mayor, chief of police -- will be redefined by this."

"This will be the third era of computing," Ms. Rometty said. "The first [era] was machines that just tabulated and counted. The second was programming -- [telling computers] do this, do that ." The third era will be driven by the immense amount of data to crunch. "In this world of big data, you won't be able to program the machines for everything they will need to know. … These machines will have to be able to learn what is right, what is wrong, a pattern. They learn. That's cognitive."

Watson, IBM's artificially intelligent computer that competed last year on "Jeopardy," was IBM's first example of this cognitive computing in action.

When people ask where Watson has gone, "I say 'Watson has been in medical school,'" Ms. Rometty said. "Since we played 'Jeopardy' with it, we have donated it to medicine."

IBM is working with several of the country's leading cancer centers in the area of oncology and has "probably ingested 80% of the world's medical data," Ms. Rometty estimated. "And if you watch it work with these doctors…. it's almost as if he's talking to a colleague" sharing probabilities around whether diagnosis or treatments are right or wrong and making other high-probability suggestions.

"So on one hand, we're doing oncology, and on the other hand we're working with banks and call centers," she said. "We've got all sides covered here."