Power is also about influence, and influence doesn't have to involve ownership. Power can be taking advantage of what is offered for public consumption and using it for your own purposes. There is power in numbers and owners are only as powerful as users and consumers make them, which is why invoking a boycott can be a form of power. Power is more than just a word; it's a dynamic. And of course in comes in degrees IMO
Leslie Jones, is a SNL member who recently made her debut in the female re-make of "Ghost Busters". She also appears in a commercial for AllState, and is a former stand-up comedienne, whose alter ego was a loud, overbearing black woman which is also the type she usually plays on SNL The fact that she is tall, dark and husky, wears her hair in a spiky natural and is given to threatening scowls, has offended a certain segment of black women who don't like what they consider her stereotypical way of representing them. Anyway, after "Ghost Busters" came out, she was blitzed with a barrage of hateful racist insults via social media "courtesy" of white movie goers, which she admits hurt and demoralized her. When she took to twitter and answered her critics, a certain amount of power accrued to her and she was suddenly popping up on TV shows, stating her case to sympathetic hosts. No, she probably didn't defuse the hate but she took proud ownership of who and what she is and cashed in on a popular outlet to squash her detractors, earning widespread results in the process.
In the old days, people used to stand on platforms to vent their grievances and sell their wares. They may not have owned the platforms but they made good use of them.