Security guys break the Mac every single day. Every single day, they come out with a total exploit, your machine can be taken over totally.

Going out in the field, it's always enlightening to see what's working and what's not and to sit down and talk - I was with young girls in south Africa - understanding why our tools for prevention aren't being adopted, and what way may need to invent to help protect them.

Today, we take the risk of nuclear war quite seriously, climate change not so much and epidemics least of all. But no single country, not even the United States, is well prepared. And even if one country is doing the right things to protect itself, it has to be a global thing.

Harnessing steam power required many innovations, as William Rosen chronicles in the book 'The Most Powerful Idea in the World.'

There is this broad, broad recognition of how technology is enabling new things. Companies that never paid attention to computers in any form now see digital technology as creating threats and opportunities for them.

With a public library card in your hand, you have access to the Internet and a world of opportunities.

We're only at the beginning of what we have to do here.