Marissa Mayer, Google's 20th employee and its first female engineer, announced today that she's jumping ship after 13 years and has accepted a job as Yahoo's first female CEO — and its fifth CEO in as many years. Google's first female engineer, she was most recently in charge of local and location services, including Google Maps, Google Earth and Zagat.

Mayer told the New York Times she considers Yahoo "one of the best brands on the Internet." Mayer had another big piece of news today: she's expecting her first child, a son, with husband Zack Broyer, a Silicon Valley investor, in October. She tells Fortune, "My maternity leave will be a few weeks long and I'll work throughout it."Continue reading...

As Internet Week kicked off in New York today, Yahoo execs were busy pitching its new advertising platform, Genome, while downplaying the weekend's executive shuffle that saw the ouster of resume-fudging CEO Scott Thompson, the appointment of Fred Amoroso as chairman, and the elevation of Ross Levinsohn, EVP of the Americas and the brand's head of global media, to interim CEO — not to mention three new board members.

"It's very damaging, and speaks so negatively to the (vetting process)," commented "ambi-practioner" Adam Hanft to USA Today. "(Thompson) was hired for strategy, branding and marketing — not computer science."

It was a short run for Thompson, former president of eBay's PayPal unit. Yahoo only named him CEO, its fourth in less than five years, on January 4th. Levinsohn, meanwhile, is stepping up while trying to reassure advertisers — as he did at the brand's recent digital upfront for advertisers with Katie Couric — to put their faith and budgets in Yahoo's original web programming and vision.Continue reading...