Adam Gurri wrote in with this excellent observation:
“When I think of something that is so abundant as to be available for free, I think of acting.
It's no secret that are are more actors in New York than there are productions to put them in. Economics helps us understand the consequences of this to a certain extent; obviously a gigantic supply will result in lower wages per actor. What interests me, however, is how this works in practice. People think that a gigantic sector of a specific workforce could not possibly work for free, because they need to feed themselves and pay their bills, and so forth.
The thing about acting is that the labor force (actors) actually value the ability to do work in that field that they are willing to take on work for nothing and take on other jobs as a sort of cross-subsidy. There is a sort of demand for employment in theater, which makes competition among actors so fierce as to actually drive down wages (at time of entry at least) to zero or near zero.
There is a parallel between this old story and what's going on in the content industries today, I think. It used to be that professional economists, physicists, statisticians, historians, and software programmers were too busy doing their jobs to write about it for the general public. As a result, newspaper and magazine writers--the majority of whom had no technical training or experience in these areas--none the less had a comparative advantage when it came to writing about these topics for broader audiences.
Today, the cost of writing on a blog that is out in the public to be seen by anyone interested in it is nearly nothing. Russ Roberts can blog about economics, Google employees can blog about their projects, and so on. The internet has made it possible for the content industries to look more like the acting industry: people giving away content for free because they enjoy it, while making money with a paying job.”