I've written before about the sometimes negative impact that commercial vendors can have on open source projects.  (See Should commercial open source vendors "own" an open source community?)  Some business models and business practices of open source vendors (trying to control all committers and commits, withholding enhancements and fixes from community versions, etc) seem to turn an open source project into something that looks a lot like a proprietary software product.  Unfortunately, these practices are becoming more and more prevalent.

One of the most popular categories of open source software is undoubtedly application servers. JBoss, Geronimo, and Tomcat are practically household names to anyone with even a passing familiarity with open source. But like any software package, every open source application server comes with its own pros and cons. Selecting the right open source application server for your environment requires detailed functional evaluations and important technology decisions on topics like EJB2 compatibility and OSGi. Further complicating the selection process is the recent release of the SpringSource dm Server, which abandons the EJB world altogether.