Lots of movement in the Most Powerful Women space. A Friday wrap-up….

Hearst Magazine chairman Cathie Black surprised the world–and people close to her too–by accepting a job as Chancellor of New York City schools. It’s not so shocking that Mayor Mike Bloomberg would hire her–they’re friends, and she is, like him, a strong manager although one who’s inexperienced in education.  Joel Klein, Black’s predecessor, also was inexperienced in education when he took the post eight years ago.

The real stunner here is that the 66-year-old Black, who is also a director of Coca-Cola (KO) and IBM (IBM), would want to run America’s largest school system. The $23 billion budget that she’ll oversee sounds sweet, but that budget doesn’t accommodate the glittery media regime she’s used to:  lunching at Michael’s, hobnobbing with Oprah, working in the elegant Hearst Tower. After hearing the news this week, one New Yorker asked me, “Is the magazine business so under siege that turning around NYC schools might be an easier gig?”

Speaking of the media biz, Time Warner’s (TWX) EVP Pat Fili-Krushel plans to leave to be EVP of Administration at NBC Universal. She should feel at home in TV land: She once ran ABC and created one of biggest-ever daytime hits, The View. At NBCU, Fili-Krushel will join two women on Fortune’s Most Powerful Women list: Bonnie Hammer, No. 45, and Lauren Zalaznick, No. 46, who plan to, despite rumors to the contrary, stay as Comcast (CMSA) closes its deal to take over NBCU from General Electric (GE). Hammer and Zalaznick are expected to pick up added responsibilities post-merger.

A few more job shifts–in Silicon Valley–worth noting, as TIME International is running Fortune’s MPWomen list in its new issue, and we alerted our TIME colleagues of these changes: EBay (EBAY) Marketplaces president Lorrie Norrington, No. 44 in our rankings, has left the company for family health reasons. At Google (GOOG), Susan Wojcicki, No. 43 on the MPW list and the force behind the company’s ad platforms, stepped up to SVP. And search queen Marissa Mayer (No. 42), whose dinner for President Obama I wrote about last month, has settled on her new title: VP of Consumer Products.

Sounds simple, but what does that mean? As the 35-year-old Mayer, who is Fortune’s youngest-ever MPWoman, explains, she now oversees “location-based services–searches looking for local information, Google Maps for web and mobile, Earth, Streetview, and more–to help make sure users get where they are going in an increasingly mobile world.”