The sultry and sophisticated editor in chief of Millennium magazine gets a lot more action in this novel, and we don't just mean of the romantic kind. Sure she gets a little love from Blomkvist, but we're talking honest-to-goodness subplots in which she stars. The trouble all starts when she accepts a job as editor in chief of a huge news organization, SMP. She fights a losing battle against a board of directors who care more about lining their pocketbooks than they do about bringing quality news to the public.
At SMP she gains a cyber-stalker, Peter Fredriksson, who went to high school with Berger and developed an icky obsession. He's miffed because she ignored him in high school and she doesn't remember him when she meets him at SMP. It's all very Veronica Mars. But, like Veronica Mars, there is more to this than cheesy mysteries. In this case, Berger's stalker becomes a way for Salander and Berger to bond, since Salander uses her hacking skills to track the villain. Plus, this subplot deepens Berger's character, showing us how vulnerable she can be.
Her absence at Millennium reveals how important she is to the magazine and the people who work there, and how important they are to her. Her work at SMP gives us a chance to see how totally tough she is, and how she refuses to bend to the gender role the guys at SMP try to fit her into. They think she's a silly woman who they can manipulate for their own purposes. So imagine their surprise when she says stuff like:
"Let's see if you understand this message. If it happens again I'm going to relieve you of your job as news editor. You'll hear bang-boom, and then you'll find yourself editing the family page or the comics or something like that." (10. 127)
Erika Berger doesn't play, and when she's pushed too far, she totally hangs her boss at SMP out to dry before going back home – to Millennium and her coworkers.