There's a lot of debate these days about the impact of the increasing number of paid developers in FOSS communities that started as volunteer efforts and still have significant numbers of volunteers. Evangelia Berdou's PhD thesis "Managing the Bazaar: Commercialization and peripheral participation in mature, community-led Free/Open source software projects" contains a contains a wealth of information and insights about this topic.

Berdou conducted interviews with members of the GNOME and KDE projects. She found that paid developers are often identified with the core developer group which is responsible for key infrastructure and often make a large number of commits. Furthermore, she suggested that the groups may have different priorities: "whereas [paid] developers focus on technical excellence, peripheral contributors are more interested in access and practical use".

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