Facebook's founder, then 24, had come to London and gave an interview to the BBC.  I hit him with a number of sceptical questions about the social network's business model, suggested "you better start worrying about earning some money pretty fast", and then turned to the takeover offers made for Facebook the previous year. It was rumoured that Microsoft had offered $10bn - but Zuckerberg had rejected all these approaches. "That looks like a mistake now," I told him. Surprisingly, he did not agree and when I suggested he could have retired at 24 he simply said: "What would I do?"
At the time, this nerdy young man in jeans and sneakers did not look like a master business strategist or the leader of the most formidable company of the next 20 years. But that is what he has proved to be.
And his final answer in that interview, where he insists that he is motivated not by money but a desire to change the world,  rings true in the light of Zuckerberg and Chan's philanthropic announcement. Mind you, a read-through the letter to their daughter reveals that their charitable aims could align with Facebook's commercial strategy. It talks about the mission to "connect the world" - which must mean more people using Facebook. And surely participating "policy and advocacy to shape debates" is code for lobbying to get politicians to share Facebook's vision of our future.
Of course, if he had taken my advice, Mark Zuckerberg would have retired by now with a paltry couple of billion dollars, and Facebook would have merged with Yammer under Microsoft's ownership. Which goes to show why he's a visionary geniusâ€¦ and I'm not.
When I heard about the move by Mark Zuckerberg and Priscilla Chan to give away $45bn worth of Facebook shares to good causes, my mind went back to 2008.