Practically all the coverage of the Instagram acquisition was centered around Zuckerberg personally. As a new CEO, her first actions bear close scrutiny, the same way Mark's did when his company was about to go public. It's not some special infatuation with Mayer specifically.
The headlines from back then:
* The Instagram Deal: A Mark Zuckerberg Production [NYTimes.com]
* Zuckerberg did $1 billion Instagram deal on his own [CNET]
* With Instagram Buy, Mark Zuckerberg Shifts Facebook Into Acquisition Mode [Forbes]
* Mark Zuckerberg Announces Instagram Acquisition By Facebook [Huffington Post]
* Instagram Was Mark Zuckerberg's Last Hurrah as Facebook's Hacker King [The Atlantic]