CodePlex projects are added on an ongoing basis into Black Duck's KnowledgeBase open-source project database. You can access to the Black Duck repository of information about open-source projects—including code that is relevant to developers who work on Microsoft projects. Moreover, developer using the Koders.com open-source search engine will be able to search for open-source projects previously available only through CodePlex.
CodePlex is an open-source project hosting site, which hosts 9,000 projects with 100 new projects added each week. The majority of projects hosted on CodePlex are for Windows and .NET development, but CodePlex accepts projects for any technology. Meanwhile, Black Duck's KnowledgeBase is a searchable database containing information on more than 200,000 open-source projects collected from more than 4,100 Internet sites.
Thanks eWeek for Black Duck, Microsoft Team for CodePlex Search.