What a difference a year makes. In the case of CodePlex, Microsoft's open-source code-hosting site, a year has seen Microsoft make serious progress toward real open-source savvy. The site has more than 120,000 registered users and 7,500 projects.
I've noted for years that open source should be an opportunity for Microsoft, not a threat. Windows, for example, should be the world's biggest open-source platform, but it's not, and Microsoft has only itself to blame for this.