I was just reading a very interesting article from Jeremy Allison of the samba team called The Land of "Nothing for free". A very interesting quote
My panel was rather uncontroversial, Microsoft, Bruce Perens and myself being on our best behavior. The only sparks that flew where when Microsoft made it abundantly clear that they would use their patent portfolio to prevent the spread of GPL software. Section seven of the GPL (the implicit patent grant of the license) now looks like the most prescient writing Richard Stallman has ever done. If you're not familiar with it I'd suggest you read it and understand why using the GPL to protect your Free Software is so important.
The article is old, but do check it out.