Will my target audience reject a .net solution?
cheriot: Two thoughts:1) The money they spend on a windows server to run your application on is money out of your pocket.2) If you will support plugins like wordpress, trac, etc, you'll have an easier time creating a plugin ecosystem with open source tools.Then again, I'm biased since I work in a linux/java/ruby shop.I'm assuming that you plan to have your customers install the application. If your target customers are the makers of software as a service, why not sell them your software as a service?