From a NY Times Article:
Like newspapers and the music business, scholarly publishing has been drastically affected by the Internet. But the differences are as striking as the parallels. Unlike journalists, most academics are paid for research or teaching, not writing. Yet all academics need to publish their work — to share and validate their research and also, crucially, to advance their careers. A scholar who does not publish regularly generally does not get promoted, making for a one-sided relationship with publishers.
Sales figures, which can often be counted in the hundreds, matter far less than impact — the number of times a publication is cited by other researchers. And most journals rely on unpaid academic peer reviewers, rather than a paid editorial staff, to select articles for publication All of which makes the economics of scholarly publishing very different from that for either newspapers, which depend on advertisers and a mass readership, or music.
“Scholars write journal articles for impact, not for money,” said Peter Suber, a fellow at Harvard University’s Berkman Center for the Internet and Society. “And while there are a lot of misunderstandings most people understand that open access is not like file sharing music or video piracy. Open access relies on the copyright holder’s consent.”
The cost of print subscriptions is just one factor in the explosive growth of open access journals like PLoS One, produced by the nonprofit Public Library of Science, which has grown from publishing 138 articles in 2006 to 6,749 in 2010, making it the largest scientific journal in the world. Unlike paper publications, PLoS One has no restrictions on the number of articles it can accept.