@DeathByVisualStudio: They are the most upfront about what they are doing. Companies like Google and Apple seem to be hiding behind the FOSS banner and using it for their own purposes, but don't seem to give back as much as they take.

Microsoft doesn't use any FOSS in their products, but gives a whole lot to the community. They aren't even pushing their own branded licenses any more and are instead using licenses that are more palatable to the FOSS fanbois.