Or, if you don't have fifteen minutes, you can read a "lightly edited" transcript on Shirky's blog. At one point he recounts talking to a television producer about a particular Wikipedia dustup.
She heard this story and she shook her head and said, "Where do people find the time?" That was her question. And I just kind of snapped. And I said, "No one who works in TV gets to ask that question. You know where the time comes from. It comes from the cognitive surplus you've been masking for 50 years."