The difference between a stranger sending you a message that you might be interested in at a very low volume level, no repetition, just sending it to very few people, and that being done as spam - those things get close enough that you want to be careful never to filter out something that's legitimate.

Making sure all our students get a great education, find a career that's fulfilling and rewarding, and have a chance to live out their dreams ... wouldn't just make us a more successful country - it would also make us a more fair and just one.

The misconception that aid falls straight into the hands of dictators largely stems from the Cold War era.

What are the top 20 universities in the world that do good materials research that might create carbon fibers to do jet stream kites or new magnets that will allow [energy] generation to be done up there and you just bring the electricity down. You either have to bring down rotational energy, which is hard, or you have to have the generator up there and bring down the electricity. Well, putting the generator up there is hard to do because it's too heavy.

The Ebola epidemic can serve as an early warning wake-up call to get ready. If we start now, we can be ready for the next epidemic.

As for drugs - well, Gates was certainly not unusual there. Marijuana was the pharmaceutical of choice.

Investing in innovation, which was my broad theme talking to [Warren Buffett ], that included health vaccines, it included energy and education.