Geoffrey Boulton et al make a compelling case for data sharing in a letter to The Lancet. Science as a public enterprise: the case for open data begins:

"The past half-century has seen a breathtaking surge in scientific discovery. We have put satellites into orbit and probed the universe; we have discovered the chemical structure of living organisms and learned to manipulate it; we have been able to read the Earth's history in minute detail from ice-sheet and ocean cores; and we have improved human and animal health through increasingly large epidemiological studies and clinical trials. All of these achievements have necessitated new ways of collecting, storing, manipulating, and transmitting information that far surpass anything previously dreamed of. The information technology that permits this has not only removed geographical barriers but also put immense power to access, manipulate, and communicate information (including scientific data) in the hands of ordinary citizens.

"Yet many of the habits of scientists have barely changed since the 18th century. Driven by curiosity, they have typically pursued their research, published their findings, usually in peer-reviewed journals, filed their data, and then moved on. But such detachment is now questionable as science profoundly changes the lives of citizens, and scientists collect more and more evidence of the human assault on the natural systems of the planet. Science has become woven into the fabric of modern civilisation and should be, and be seen to be, a public enterprise, not a private enterprise done behind closed laboratory doors."

Boulton goes on to say: "Scientists have tended to regard their data as personal property. After all, it is they who worked hard to generate it-and ownership has never been seriously challenged." He then goes on to provide four reasons why an open attitude to data sharing needs to develop, as well as providing insight into the challenges and issues.

Well worth a read.