Say what you want about Microsoft, but few companies are investing so much resources on open source projects.
Linux Foundation presented the contributors to the Linux project recently, and Microsoft is on top 20 list. At Microsoft Openness website you can read more about Microsoft's broad commitment to open projects: http://www.microsoft.com/en-us/openness/
In terms of Joomla Microsoft has worked tight with Joomla team to, among other things makes it possible to use Microsoft SQL database to Joomla which now since version 2.5 possible. Microsoft has also developed with Joomla in their WebMatrix function where it is easy and free to publish web pages built on Joomla. Read more about WebMatrix and joomla here: http://www.microsoft.com/web/joomla
As if that were not enough with the above are also Microsoft Gold Sponsor of this year's "J & Beyond" in Frankfurt where we Joomlaproffs.se will participate.
Thank you for your Microsoft demonstrated support for the Joomla platform!