Open source programming tool on the rise: Eclipse (and the Eclipse Marketplace)
It's hard to write about programming tools without mentioning Eclipse. While the IDE is well-established, plug-ins continue to re-invigorate it. Plug-ins exist for practically every important language available. PHP, Ruby, Python, and C all live comfortably in this IDE, thanks to the evolving plug-in ecosystem.
Almost as important are the sophisticated ecologies that support these plug-ins, many of which are open source. The Eclipse Marketplace is one such site devoted to helping users discover the tools they need. The site includes a social networking layer, showing who likes a particular plug-in and which plug-ins offer similar or competing solutions, thereby opening your search beyond simple lists of the most popular or the most downloaded.