It is a slow news day for a call to be made to make Windows open sourced! What will they suggest next? Oracle? MS Office? What possible advantage would MS (and other closed source vendors) gain in going the open source route? From my point of view, very little really. There are some immediate gains. Some measure of goodwill on the part of the FOSS community and, depending on the open source license used, the gradual growth of a community around those products. The key differentiating factor is the type of license. OpenSolaris has next to no community around it because of their CDDL prevents mixing of code with GPLed stuff. Why bother then?