In an excellent interview, Tyler Cowen is asked about blogging:
Knowlege@Wharton: You are a writer and co-founder of the popular economics blog MarginalRevolution.com. How does your inner economist explain blogging? What is the incentive for people like yourself to offer high-quality goods and services online for free?
Tyler Cowen: Blogging is fun. I’ve made friends through blogging, but most of all I have learned a lot. I think it has made me a better economist. I would also say it’s helped me to discover my inner economist. Because when you are blogging for real people, they don’t want techno babble. They don’t want jargon. They’re like, “What can you tell me that I actually care about?” Most of the ideas in this book, in one way or another, came out of blogging.
Knowlege@Wharton: So we can be motivated to do a lot of work, even highly skilled work, just because it’s fun?
Cowen: Absolutely. A lot of science works on the same basis. It’s true that scientists get paid, but typically they don’t get paid more, or much more, for discovering something that will make them famous. They do it because they love science, or because they want the recognition or because they just stumble upon it. Einstein was never a wealthy man but he worked very hard. So blogging is a new form of an old idea: that people do great things for free. Adam Smith didn’t get paid much for writing Wealth of Nations, even though it’s a long book that required a lot of work. He had an inner drive to get his ideas out there.
I’ve often been asked, and have often asked myself, why I blog. I spend more time on it than any other productive activity, and make only a small fraction of an anyway-insignificant income from it. The above excerpt answers the question rather well.