This is an open source initiative to provide a centrally managed and globally accessible database of security vulnerabilites across an extensive realm of products.
Their manifesto as presented on their web site:
"OSVB is an independent and open source database created by and for the community. Our goal is to provide accurate, detailed, current, and unbiased technical information".
They also have an XML-RPC based service for programmatic interaction at: http://www.osvdb.org/xmlrpc-server-client-documentation.php