Everywhere you turn these days, the term “citizen science” is in use. The National Wildlife Federation (NWF) dedicates a page of its website to the topic. In July, the Ecological Society of America (ESA) published a supplemental journal devoted wholly to the topic of citizen science—its history, current status, and potential for the future.  When staying with friends last week, I had my morning coffee in a mug labeled “Central Valley Winter Raptor Count – 2008-2011,” an excellent example of citizen science.

But, what do we mean by “citizen science”? Historically, the practice of involving members of the public in various scientific projects was viewed as an opportunity to...