It was June 2, 2010, when a sweat-soaked Mark Zuckerberg found himself struggling to defend his company's policies on the stage of All Things Digital's D8 conference.
"It's ok, do you want to take off the hoodie?" pleaded co-host Kara Swisher, watching the sweat accumulate.
"No, I never take off the hoodie," he responded.
He rambled for minutes with vague conceptual answers to direct questions about Facebook's privacy settings.
It was the nadir of his public speaking life and it cemented detractors' view that Zuckerberg was robotic, unfeeling, and unready for prime-time. "Zuckerberg Has Meltdown Over Privacy" read one of many disparaging headlines.
It was at that moment that Zuckerberg got serious about his problem, says his friend, blogger and former Microsoft "technical evangelist" Robert Scoble in a Quora post about his public speaking transformation.
"After that ... he came back and had a deep look at himself," writes Scoble. "His sister, Randi, went over his house that evening and gave support ... I said he should quit the CEO job, because he wasn't having fun ... Instead he found a way to have fun with it."
Scoble says Zuckerberg enlisted the help of Facebook COO Sherly Sandberg and VP of communications Elliot Schrage.
"They usually are by his side and give him advice," he writes. "Both are very confident and good on stage (Sheryl gave an awesome TED talk last year and this year I watched as she interviewed Bill Gates and Bono and seemed better to me than old pros at that game)."
Scoble also says dealing with the controversy surrounding David Fincher's The Social Network gave Zuckerberg the confidence that "even when his critics throw the entire kitchen sink at him (in this case Hollywood's best) it doesn't really hurt him."
Another factor has been his girlfriend Priscilla Chan, who Soble says has encouraged him behind the scenes and has played a similarly supportive role as Melinda Gates has to her husband Bill Gates.
Now looking at Zuckerberg cracking jokes on SNL and speaking candidly on Oprah, it's astonishing to think that his All Things D appearance was just one year ago. Reflecting on the transformation, Scoble says "It's like swimming in cold water. At first when you jump in you just aren't able to think. It's a foreign environment. Then, after doing it for a while, your system gets used to it and, indeed, starts having fun with it."