They lead, they follow, they help, they communicate, participate, and cooperate. They are a godsend to every project they touch. They know people because people want to know them. So they can act as a point of connection, as a ``friend of a friend''. They can always be reached. They always answer their mail. They work hard for important causes and are known for their work.
Think of Richard Stallman. He wrote huge piles of code. In fact, he wrote or helped write a lot of the code you call ``linux'' as part of the ``GNU'' project. He's always being asked to give talks (he was speaking to the president of India this week). He is always on the road. Yet every email I ever sent him (and I've sent about a dozen) always, always gets an answer. And he programs while he's on the road. He's a very rich man in the gift culture even though he's not financially well off.
They say that in the land of the blind the one-eyed man is king. In the gift culture, Mother Teresa is queen.