A wealth differential can become a strain on a friendship. Some people who suddenly become wealthy reconvene their former social group as an entourage to overcome it. Others just drift away from their old friends and make new friends.

If you had more money than everyone else you already knew, combined, would you feel any obligation to do anything to make their lives better? It doesn't even have to be anything big. If I were CEO of Apple, I think I would, at the least, give away copies of the major hardware product releases to my oldest friends just before launch day, with prepaid support. You don't need to hand out cushy sinecures, but those are fine, too, provided it's from your personal bankroll, and not your company's.

I certainly wouldn't shut down my company's existing philanthropic programs, and never leave any public trace of charitable giving whatsoever.

Hell, I'm not even rich, and I put $500 into an old high school friend's first Kickstarter project. If I had more to contribute, I would have contributed more.

It may not be an absolute quality all nerds need to have, but some generosity towards friends and family is a requirement for me, specifically, to like someone.

Gifting etiquette varies by person, even within the same culture, but I expect rich people to give to charities and put their names on museum galleries and hospital wings and university buildings and zoo habitats and park playground equipment. I also expect them to show up to award ceremonies and accept their mantelpiece trophies with good grace and concise speeches. That's what lets the rest of us know they are not completely self-absorbed assholes. When your success rests upon so many people that you cannot possibly thank each of them personally for their support, that's how you show gratitude to "the public".