This article, titled “Myths Open Source Developers Tell Ourselves“, dates back to 2003, but is surprisingly accurate. I suspect these myths will become even more prevalent; the number of open source projects out there has been increasing year after year, or at least that’s my impression. (Is there any person or organization that’s trying to track the number?) My favorite myth in the article: “End Users Love Tracking CVS”.
A running description of activity related to DragonFly BSD.
Regarding the number of open source projects, two relevant sites that collect (incomplete) open source metrics are http://cia.vc/ and http://www.ohloh.net/. Also, there are the free providers like Sourceforge, code.google.com Subversion hosting, savannah, etc.
There is also a “code search” product on Google Labs which searches open source repositories and the like : http://www.google.com/codesearch. It would be interesting to see how the indexable repositories of open source code have grown over time, but this isn’t exposed through the site as far as I can tell.