Philanthropy should be voluntary.

I'm an investor in a number of biotech companies, partly because of my incredible enthusiasm for the great innovations they will bring.

Who can afford to do professional work for nothing? What hobbyist can put three man-years into programming, finding all bugs, documenting his product, and distributing it for free?

I've been very lucky, and therefore I owe it to try and reduce the inequity in the world. And that's kind of a religious belief. I mean, it's at least a moral belief.

If you want to build a great company, get the hell out of Silicon Valley.

[We in Microsoft] are not the only software company but we are a great software company doing some unique work.

Another trick in software is to avoid rewriting the software by using a piece that's already been written, so called component approach which the latest term for this in the most advanced form is what's called Object Oriented Programming.