This posting is a refinement of a concept that I presented earlier: Using OSS to disrupt industries.
Through the title, I am suggesting that there are negative network-effects in the form of social impact with open source systems. In fact, I'll go so far to say that open source software can be used to collapse entire markets, both IT and non-IT. Much like having access to capital allows you to invest in ventures that often times generate more capital (once rich it's easier to become super-rich), the more available source code is, the easier it is to free-up more and more source code.
It also can cause closed-source projects to collapse (or at least their market to reduce) as more and more adopt open practices. An unfortunate fact though is that information walling often results in more jobs. The more hops information has to take, the more jobs were created to get there. How many people got put out of jobs because automation happened in the phone switch industry? I believe the same thing will soon be happening to those in the open source industry as the industry turns inward and puts itself out of work. First it'll be some projects taking each other out of the next few years thanks to market forces but at least in the Drupal community, I'm already seeing cracks.
People at the top asking for more and more control over the platform, even though it's the very thing that they went to open source to get away from. Here are some other examples I could come up with of where giving away code has far greater consequences then just giving code away.
Open source is an iterative process which leads to the open sourcing of more technologies that enable more people to do more with less technical knowledge. Apache leads to PHP / MySQL leads to Wordpress / Drupal systems. As a result, I've seen Dreamweaver (as an example) go from a tool that I used to build websites to a tool that I use to build code to allow others to build websites. This is the creative and destructive power of open source.
This doesn't have to just be contained to software platforms though. Wikipedia, leads to freer access to information, leads to marginalization of paid information sources (books, Encarta, etc) which collapses the previous silo-ing of knowledge in sources that had a cost of entry.
Previous web-development shops had coders, site layout and design, producers, copy editors, graphic artists, server manager, all with different talents and skills. Now with the web landscape being as it is, the cost of entry has been lowered for everyone. As such, I don't need to know layout / design because of captured, open knowledge, in the form themes / templates. I don't need copy editors (or as many) because everyone can self-moderate content as well as use small publishing workflows to release content. Server management consoles exist and captured knowledge in the form of things like MAMP and XAMPP (not to mention open source based services like wordpress.com) make it easy to get a site up and off the ground. Come to think of it, I don't even need me, the coder, because other coders have captured install and configuration knowledge in the CMS like wordpress.com.
No, the only person "needed" to produce a high quality website with new content is the content author and maybe a manager (though those could be the same person).
What's the trend I'm seeing currently? We're going from a world where there are less hubs and less authorities. Where information can be created and disseminated so quickly that newspapers and traditional TV media aren't going away entirely, but are definitely being softened in tone. If I want an opinion I can go anywhere and get it and that's great (most people already know this).
But what I also see happening, is that we're collapsing our own industry. I see less and less people wanting to get into the IT sector because those that have come before them have made things so easy, so wyziwig'ed, so fast that it's not interesting to them. This will lead to less ideas, less choice, and only a few technical authorities who can effectively kick the door shut on all those who come after them. A truly, Apple (and a few others) world of elite companies as well as a few elite open source advocates along for the ride.
Connect the dots, speak out for more choice, question why someone is giving you something for free ;).