How Often are Internal IT Projects Open Sourced?

An anonymous reader asks: "Most open source projects seem to started by individual contributors working in their personal capacity. I am thinking about projects like attendance maintenance systems, and not high-end infrastructure projects like Sun's Solaris. Most internal IT products are probably reimplementations of what exists at other companies, and do not bestow any competitive advantage to the developing company. The cost of developing the software is overhead, and they could potentially save money by open sourcing the projects and utilizing contributors' expertise. So, are there lots of instances of companies' internally developed IT products being open sourced?"