SHE made over $100 million last week and is number two at the world's largest social networking site.

But Facebook's chief operating officer Sheryl Sandberg has been slammed by an army of angry commenters after advertising for an unpaid intern at her community organisation Lean In.

The ad was posted on Facebook yesterday by Lean In's New York-based editor Jessica Bennet, who said the organisation wanted an editorial intern to work part-time, unpaid until the end of the year.

"Wanted: Lean In editorial intern, to work with our editor (me) in New York. Part-time, unpaid, must be HIGHLY organised with editorial and social chops and able to commit to a regular schedule through end of year. Design and web skills a plus! HIT ME UP. Start date ASAP," it reads, with a link to the Lean In global community - an organisation which seeks to advance the role of women in the workplace.

Readers were not impressed, with nearly 100 comments at the time of writing slamming Sandberg for not paying her staff.

Nick Wurl wrote "Sheryl Sandberg made [US]$91,000,000 last week. Won't pay an intern a market wage. Me thinks her "lean in" campaign is merely for personal gain/publicity and that she doesn't really seek any kind of real equality. Actions speak louder than words."

Renea Henry said "you can lean in - if your parents or partner can pay for it. you work for no wages at Sheryl Sandberg's vanity project while she asks why there are no other women at the table willing to change the world. spoiler alert: it's because they needed a job that paid actual money so they could feed themselves and their families."

The advertisement comes just days after Sandberg, 43, who is ranked sixth on Forbes list of most powerful women in the world, sold more than $100 million worth of Facebook stock after the share price edged above $41.

She still holds more than 25 million shares in the company, representing about $1.09 billion, according to the filing, released late on Friday.

Internships are also in the spotlight in the US after unpaid workers launched a wave of lawsuits against media companies such as Fox Searchlight Pictures, NBC Universal, Gawker, the Charlie Rose Show and Conde Nast in recent months.

Editor Jessica Bennet jumped in to defend herself against the angry comments, posting: "Deep breath. Since I joined Lean In, many people have reached out asking if they can volunteer - and specifically, intern. This was MY post, looking for a volunteer to help me in New York. LOTS of nonprofits accept volunteers. This was NOT an official Lean In job posting. Sorry for the confusion."

However, people weren't buying it, with many pointing out if she wanted a volunteer she should have asked for one in the first place.

Liv Pratez wrote: "Can you not see the hypocrisy? Lean In an organisation about Women, Work and Leadership seeks an 'intern' with skills and who can commit to a regular schedule. That's not an internship, it's exploitation. Pay your interns and the irony will be gone. Or ask for volunteers."

Herbert A Samuel posted: "Epic Fail. You wrote (emphasis mine): 'Wanted: Lean In editorial intern, to *work* with our editor (me) in New York. Part-time, *unpaid*'. Normally work means pay. Unless, of course, you're a slave, or a woman, or something."

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