Clay Shirky gave the best keynote talk that I caught at Web 2.0 Expo last week. He’s posted a transcript, entitled Gin, Television, and Social Surplus on his new book’s site (also quite recommended; it makes it onto my “understand the internet” bookshelf).

So how big is that surplus? So if you take Wikipedia as a kind of unit, all of Wikipedia, the whole project–every page, every edit, every talk page, every line of code, in every language that Wikipedia exists in–that represents something like the cumulation of 100 million hours of human thought. I worked this out with Martin Wattenberg at IBM; it’s a back-of-the-envelope calculation, but it’s the right order of magnitude, about 100 million hours of thought.

And television watching? Two hundred billion hours, in the U.S. alone, every year. Put another way, now that we have a unit, that’s 2,000 Wikipedia projects a year spent watching television. Or put still another way, in the U.S., we spend 100 million hours every weekend, just watching the ads. This is a pretty big surplus. People asking, “Where do they find the time?” when they’re looking at things like Wikipedia don’t understand how tiny that entire project is, as a carve-out of this asset that’s finally being dragged into what Tim calls an architecture of participation.

If you didn’t catch it, this is well worth reading.