The increased spread of free software, both due to its form of development and its use, generates other related markets that have been exploited by diverse companies:
Community and development: perhaps the most obvious examples are those that provide hosting services and collaborative tools for software projects, such as SourceForge, CollabNet or Freshmeat. There has also been a proliferation of code search engines, including Google Code, Koders, Krugle and Codase.
Legal certification: companies offering this type of certification are also becoming increasingly relevant. They ensure that a software or particular combination is legally possible and are familiar with the licensing problems it could have. This service is provided by the companies we saw earlier, such as the creators of platforms and bundles, like SpikeSource, but others have sprung up that focus entirely on legal issues, such as Black Duck and Palamida.
Sale of books: O'Reilly and his books are one of the most often cited examples in this category.
Merchandising: we should not overlook the importance of merchandising as a supplementary or even main form of financing. Examples include ThinkGeek, a subsidiary of SourceForge, which contributes revenue through Internet sales of various types of product for "geeks": from t-shirts and mugs to a range of gadgets.