Bottom-up is a really bad way to think about it because there is no bottom. In an era of grassroots change, the top of the pyramid is too far away from where the action is to make much of a difference. It takes too long and it lacks impact. The top isn’t the top anymore because the streets are where the action is. The new leverage available to everyone means that the status quo is more threatened than ever, and each employee now has the responsibility to change the rules before someone else does.