How to manage casual contributors to open source projects: 
Increasingly, people want to contribute to projects casually—when they want to, rather than adhering to a schedule. This is part of a broader trend of “episodic volunteering” noted by a wide range of volunteer organizations and governments. This has been attributed not only to changes in the workforce, which leave fewer people able to volunteer with less spare time to share, but also to changes in how people perceive the act of volunteering. It is no longer seen as a communal obligation, rather as a conditional activity in which the volunteer also receives benefits.
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