The current issue of the New Yorker has an intriguing profile of Sheryl Sandberg, the woman Mark Zuckerberg poached from Google in 2008 to become Facebook's chief operating officer.

As well as how it offers an insight into the simmering rivalry between these two internet giants, the piece is also worth reading for its discussion of the role of women in big business.

Sandberg doesn't describe herself as a feminist, although she is keen to increase the number of women at senior levels in tech companies (Facebook's six-man board is just that -- all men). The piece discusses juggling work and motherhood, the dearth of female engineers and whether asking about maternity leave is a "girl question" that makes a woman seem weak.

But, for me, there are two key insights. The first is that both men and women still find the idea of a woman in a high-profile role sufficiently unusual that it often provokes a negative emotional reaction:

Sandberg says she eventually realised that women, unlike men, encountered trade-offs between success and likability. The women had internalised self-doubt as a form of self-defense: people don't like women who boast about their achievements. The solution, she began to think, lay with the women. She blamed them more for their insecurities than she blamed men for their insensitivity or their sexism.

In a Ted talk, Sandberg reiterates this point: not enough women negotiate their salaries when entering a job, she believes (57 per cent of men do, against 7 per cent of women). And women are still lumbered with the lion's share of housework and childcare. Woman need to find a "real partner" at home and become more assertive at work.

The second point I found interesting is the one raised by critics of Sandberg's pull-your-socks-up-ladies approach: that it is difficult for women to negotiate the patronage system in companies when the bosses are all male.

Sandberg was lucky enough to be "sponsored" in her early career by her former tutor, US Business Secretary Larry Summers -- but for many women, being "taken under the wing" of a senior male executive would not be an entirely positive move.

The profile's author, Ken Auletta, quotes a paper by Sylvia Ann Hewlett, director of the gender and policy programme at Columbia, published in the Harvard Business Review:

Sponsorship, which often involves an older, married male spending one-on-one time, often off-site and after hours, with a younger, unmarried female, can look like an affair; and the greater the power disparity between the male and the female, the more intense the speculation becomes that the relationship is more than professional. If the woman is subsequently promoted, her achievement will be undermined by office gossip that she earned it illicitly.

Those are just a couple of highlights from a nuanced and wide-ranging piece, which doesn't pretend there are easy answers to the questions it poses. If you're interested in why women are still underrepresented at middle-management and boardroom level, it goes beyond the usual "They don't have a killer instinct"/"They drop out and have babies"/"Most businesses are institutionally sexist" lines and offer a few (sometimes uncomfortable) suggestions. Yes, it's long -- 8,000 words -- but well worth a read on a drizzly weekend afternoon.