I just came across excellent open source CRM framework for .NET developers.  DNN (http://www.dotnetnuke.com/) .  I am .NET developer but love open source concept.  Until recently .NET had nothing open and more available then Starter Kits.  Though lately I notices Microsoft tendency to work and encourage open source community. 

Microsoft started to partner with non-Microsoft platforms and open source communities and showed great signs of openness and support.  Now it can run PHP on IIS, run Apache on Windows,  have different combinations of non Microsoft platform to work together like combining your project with PHP – SQL, IIS-PHP, .NET – MySQL and so on.

I was looking for open source CRM like Drupal and Joomla .  Even though I could run on current Microsoft infrastructure, due to the lack of extensive PHP experience I was reluctant to use it even though it did not require much development and just needed configuration.  However, I feel more comfortable to work in the environment I am professional in due to the fact that I know I will end up developing many modules and extension.  Then I stumbled upon DNN and started to investigate it.   I just started so it is too early to say on how I end up using it  but it looks like very extensive .NET open source CRM framework with large developer and user base and large number of modules, flexible , extensible and so on.  I will post later as I get to experience it.