If private funders of scientific and scholarly research want to maximize the impact of their investments, they should condition their funding on a promise from grantees to make any resulting peer reviewed journal articles openly accessible on the Internet within a reasonable time after publication.
To date, the most prominent private funder on this front is the United Kingdom's Wellcome Trust, which funds medical research and requires resulting articles to be deposited in PubMed Central or UK PubMed.
Private philanthropies in the United States have lagged on open access. But the tide is finally turning. On November 12, 2008, Autism Speaks, the United States' largest autism advocacy organization announced that effective December 3, 2008, all researchers who receive an Autism Speaks grant will be required to deposit any resulting peer-reviewed research papers in the PubMed Central online archive, which will make the articles available to the public within 12 months of journal publication.
This is a very important initiative. As Peter Suber notes, advocacy organizations that seek cures for particular diseases should have a particular interest in making sure that their communities have access to published research. I would add this is further evidence to refute the elitist argument against open access.
To learn more about Autism Speaks, see www.autismspeaks.org