Who has it? How do they wield it? Whom does it affect?How do you measure power in the 21st century? Each year we rank the most influential LGBT people in American culture. It's not an easy task, and we take into account a variety of criteria: everything from someone's political clout or visibility in the media to how they impact our economy and our view of the world. It's an impressive group of movers and shakers — and the changing look of the list indicates an expanding and inspiring sense of what it means to have power in 2015.