From the blog:
In our professional lives, he says, we tend to be either givers, takers, or matchers. Most of us are matchers. We’re willing to give — to help others — but we expect something in return. Matchers live in the world of reciprocity, tit-for-tat, and Even Steven. A few of us, meanwhile, are takers. Our style is to get more than we give. (Spoiler alert: Research shows that we hate takers and root for them to fail.) And a few of us are givers. We give more than we get — with no expectation of return.
See the talk Adam gave at Google about "Give and Take":