Watching Andrew Keen mercilessly beat up the strawman he creates for open source, I was tempted to leave the flame-bait post alone. But then I realized that Keen doesn't mean to beat up on open source - he actually agrees with it. He simply doesn't understand how it works. He is about a decade behind the times in terms of understanding open source, so consider this a Primer on 21st Century Open-source Economics.
Mass unemployment and a deep economic recession comprise the most effective antidote to the utopian ideals of open-source radicals. The altruistic ideal of giving away one's labor for free appeared credible in the fat summer of the Web 2.0 boom when social-media startups hung from trees, Facebook was valued at $15 billion, and VCs queued up to fund revenue-less "businesses" like Twitter. But as we contemplate the world post-bailout, when economic reality once again bites, only Silicon Valley's wealthiest technologists can even consider the luxury of donating their labor to the latest fashionable, online, open-source project.
It's unclear when Facebook and Twitter came to be even remotely connected with open source, but here's a clue, Keen: open source doesn't depend on peace-loving hippie radicals with either free time or free cash to burn. Open source is a free market,that depends upon M-O-N-E-Y. It has been for at least a decade, and the economic downturn only sharpens its value to money-grubbing capitalists.
Will an economic downturn slow open-source development? No, because open source is an effective(give away what your competitor values, and charge for your own differentiation), serve customers (lower prices, better software), and get software into prospective customers' hands cheaply and widely.
Are there people that contribute open-source software without expectation or realization of payment? Sure. But they're in the minority on the projects that matter most. For example, Linux isn't going to get hurt by a downturn: IBM, Red Hat, Intel, Novell, and others will probably increase, because Linux lowers the cost of selling other services or hardware (Intel, IBM) or provides the basis of a software business (Red Hat, Novell).
In short, it might keep Microsoft and others comforted at night to imagine open source getting hurt in a downturn, but dreams don't put food on the table. Open source does, and that's why it's going to have a happy, healthy life during an economic recession.