Open source, as a meme, is a successful one.  It is also a confusing one because open source often means free software.  I am for open source, but I am against wholesale adoption of free software because I believe it harms the health of software industry.

I typically write free open source software and tools for bleeding edge technologies.  I have written one of the first implementation of W3C DOM API while the spec was still being worked on.  I did this for the XML community so they could start using the API early and provide feedback to the DOM WG.  I have stopped working on my DOM implmentation after many DOM implementations became available.  I felt it was time to encourage commercial development.

Well, the XML tools market didn't work out as I hoped.  With continued flood of free open source (often Java) tools, XML tools market is mostly dead.  Why should anyone pay for XML parsers, editors, databases, and servers?

Free open source software devalue commercial software and poisons the marketplace.  If some talented individual started giving out free Microsoft Word clone with source code, not only will Microsoft stock drop by 25%, entire word processing market will disappear.  Once buys starts thinking that something should be free, there is no turning back.

One might argue that adding new features could revive markets decimated by free software.  New features has leverage only during early half of a product category's lifecycle.  Word processing market is already well past the halfway point.  I measure halfway point as the point where 20% of product feature set meets 80% of user's needs.  Past that point, users start caring less about new features.