Marissa Mayer 1, glass ceiling 1

Marissa Mayer, already one of the most powerful women in Silicon Valley, is off to run Yahoo.

The news generated, as CNBC's Kelly Evans tweeted with justifiable exasperation, the usual flurry of "analysis" that greets women doing things.

That commentary included various assertions that Mayer's ascent represented a shattering of the glass ceiling.

But wait, there's more. Mayer revealed after the Yahoo news broke (and after the US equity markets closed) that she and her husband are expecting their first child in October.

Appointed CEO of Yahoo and several months pregnant? Surely she's smashed that glass ceiling into smithereens.

No.

Ann Marie Slaughter - she of the most recent discursion on women and 'having it all' - rightly noted that Mayer is not 'just' a woman. She is, as Slaughter put it, superhuman, rich and in charge. Mayer can afford an army of nannies, chefs and drivers. And she's the one calling the shots at Yahoo.

And, nowhere discussed, Mayer is white. Privileged white motherhood is vaunted in America in a way that mothering by women of colour is absolutely not.

And even with that arsenal of wealth, privilege and power at her disposal, consider Mayer's own words: 'my maternity leave will be a few weeks long, and I'll work throughout it'.

Mayer is wildly successful, a testimony to her talents and discipline. But that glass ceiling remains intact - for Mayer and her cohort, women of her ilk and power, and certainly for the vast majority of women in the workplace.