You’re an astronomically wealthy tech mogul who has mastered the art of getting people to spend money with your company over the internet. How do you come up with fresh ideas for giving some of your fortune away?

If you’re Jeff Bezos, the founder and chief executive of Amazon.com, you fire up Twitter, naturally.

On Thursday, Mr. Bezos sent a tweet to his more than 222,000 followers asking for suggestions for philanthropic giving. He specifically asked for ideas that could help the world in the near term, a contrast to long-term personal investments he has made in for-profit companies with social impact, like Blue Origin, a space firm, and The Washington Post.