Oxite. The source code for the software is available under the Microsoft Public License. While Microsoft mostly describes Oxite as a blogging platform, the Oxite team also points out that you could use it as a content management system to develop more or less any type of site. Oxite currently powers Microsoft's own Mix Online and also uses some recycled parts from Channel 9 .Today, Microsoft released an alpha version of its own open source content management system,
Some of the major features of the software include support for Gravatars, pingbacks, trackbacks, RSS feeds, commenting, and the MetaWebLog API (so you can use your favorite blogging client to post to your Oxite blog directly).
The major roadblock for a lot of potential users, however, is that Oxite is an ASP.NET application, and most standard hosting services run Linux servers, which can not run ASP.NET. This, of course, makes sense, given that Oxite is also meant to be a demo for the ASP.NET MVC framework, but it will surely disappoint a lot of users.
Channel 9 has a short interview with the developers that describes some more of the software's features and the history of its development.
Given that Microsoft uses Oxite to run its own Mix Online site on top of Oxite, it must surely be a stable and powerful platform, especially for sites with multiple blogs.
However, it definitely would be too early to say that Microsoft is competing with Wordpress, Typepad, Drupal, or Joomla. There still seem to be a lot of missing pieces and we are not even sure yet if Oxite features an extension architecture that third-party developers would be able to develop for. However, it's nice to see Microsoft release this project under an open source license, even if it is at least partly for self-serving reasons.