Jimmy Wales' Wikipedia TED Talk

Jimmy Wales is the creator of Wikipedia - or at least the base concept. In this 2005 TED talk, he talks about how Wikipedia came to be, how it operates, and how many people the non-profit organization WikiMedia employs: one. He's the lead software developer and he's only been employed there since January 2005. Everyone else is a volunteer, a random person on the internet who contributes simply because they care.

Also noteworthy: Jonathan Zittrain's TED Talk 'The Web as Random Acts of Kindness'. The Wikipedia content starts at around 9:15, but it's all good.