NEW YORK — Recently I learned that I don't have cancer. My doctor called and said, "I have some good news!" Fortunately, we were in the middle of a fire drill in my office at the time, so no one noticed as I blinked back tears of relief.

I had found the lump almost two weeks earlier, while at a conference in South Africa. I returned home early to have a biopsy, but the pathology lab was achingly slow; days passed with no word. Clearly they were working hard to figure out exactly how bad my condition was. In fact, they were working hard not to miss anything before they concluded that my tumor was rare but benign.

I had been preparing for the diagnosis for more than a week . . . and to some extent for years, as I turned my investing focus from "all things Internet" to all things health-related. It turns out that understanding and promoting health is a great application of information technology. Health increasingly involves numbers. Many of those numbers aren't just medical probabilities; they concern daily life choices that you can make before you get sick (or are threatened, as I was).