I want to remind people to look carefully at the source of your information in order to determine credibility. A recent IDC study, sponsored by Microsoft, found that when most organizations migrate from Unix, they migrate to Windows, not Linux. I have been involved in enough market research to know that the questions asked can have a large impact on the results of any study. Maybe this study is accurate, but I would tend not to rely on it to support any arguments the same way that I would not rely on a report sponsored by a Linux vendor to answer the same research question. The best data comes from un-sponsored research conducted by an independent, neutral third party. Many organizations have a vested interest in open source (positive and negative), and many studies are sponsored by organizations on both sides of the open source vs. proprietary software debate. As a result, it is especially important to evaluate the credibility of our sources.
I am reminded of the famous saying, “lies, damned lies, and statistics”, which has been attributed to various people including Mark Twain and Benjamin Disraeli.