In response to an earlier post where I noted that 50% of JBoss deployments are on Windows, a reader wrote in to ask whether that was really true or whether it was simple Microsoft spin. I wrote to Bill Hilf, Microsoft’s director of Platform Technology Strategy, who said those were the numbers given by JBoss when Microsoft and JBoss announced their deal to get tighter integration between the JBoss management system and Microsoft Server products. I found the announcement on the JBoss web site and dug out the precise quote: “Microsoft Windows is used, for either development or production use, within almost half of the JBoss user base”. The “development or production” might be wiggle words, but I think it’s pretty common within the industry. See, for example, this story about database deployments: “In our survey, 90 percent of our developers work with or deployed to Windows platforms”. Still more evidence for my contention that Windows is the dark economy of open source use, the hub of activity that is rarely spoken of.