Teaching's hard! You need different skills: positive reinforcement, keeping students from getting bored, commanding their attention in a certain way.

Bitcoin is a technological tour de force

Now, we put out a lot of carbon dioxide every year, over 26 billion tons. For each American, it's about 20 tons. For people in poor countries, it's less than one ton. It's an average of about five tons for everyone on the planet. And, somehow, we have to make changes that will bring that down to zero.

Humanity’s greatest advances are not in its discoveries – but in how those discoveries are applied to reduce inequity. Whether through democracy, strong public education, quality health care, or broad economic opportunity – reducing inequity is the highest human achievement.

The vision is that people should have the ultimate in convenience. Being able to get the things they care about on the appropriate device.

Corruption is one of the most common reasons I hear in views that criticize aid.

The current information revolution is a cultural revolution, a social revolution, a thoroughgoing technological revolution that involves not just information, but labor, leisure, entertainment, communication, education, culture and thus is part of a major cultural and social shift.