Did you know that Facebook COO Sheryl Sandberg could have been the CEO at another huge social networking company? Probably not. But apparently she reveals that story and more in her upcoming book Lean In: Women, Work and the Will to Lead.

Tom Gara at The Wall Street Journal got an advance copy of the book and posted his thoughts late Tuesday. Since then, he’s been pulling out some interesting anecdotes about her time at Google, relationship with Mark Zuckerberg, and more.

One little nugget comes in the form of a declined job offer from 2006.

Apparently, LinkedIn founder Reid Hoffman approached Sandberg and asked her to be the CEO of his company.

Here’s a direct quote from the book:

“In the summer of 2006, a tiny start-up called LinkedIn was looking for a new CEO, and Reid Hoffman, LinkedIn’s founder, reached out to me. I thought it was a great opportunity, and after five years in the same position at Google I was ready for a new challenge. But the timing was tricky. I was thirty-seven years old and wanted to have a second child. I told Reid the truth: regrettably, I had to pass…”

Of course, LinkedIn would go on to hit 200 million members by the end of 2012.

I think it’s safe to say that Sandberg did well for herself at the company she eventually chose, which has also become pretty successful over the past six years.

Lean In: Women, Work and the Will to Lead is due out on March 11th.