An anonymous reader writes "Ars Technica has a story up about an estimate done by the Software Freedom Law Center of how much purchasers of Microsoft Windows are paying in 'patent taxes'. 'SFLA took the total of $4.3 billion dollars in legal costs for Microsoft from 2001 to 2004 and divided it by estimated sales of Windows XP over the same period — approximately 200 million copies — to come up with the $21.50 estimate. The organization added that North American and European customers, who pay more for Windows licenses than customers in other parts of the world, actually ended up paying more of this patent tax, and that people who pirate Windows pass their share of the tax on to paying customers.' The article goes on to point out several flaws in the study's logic. For example, the actual cost of a Windows OEM hasn't increased in the last few years; Microsoft isn't passing this cost directly on to the consumer."