Open source - Any software whose code is available for users to look at and modify freely. Linux is the best-known example; others include Apache, the dominant software for servers that dish out corporate web pages. [taken from a Google search for "open source"]

Category is for web sites and newswires that provide open source news which is in some way unique. Sites that just display a collection of news feeds from other sites and don't offer any unique content of their own will not be included.