It's actually pretty clear, Microsoft is extorting small players. If Microsoft had patents that were actually valid it would go after IBM, Intel, Google or Red Hat. They all have more money and use Linux far more widely and deeply. But Microsoft doesn't go after those companies because it would lose those cases. Microsoft is targeting companies without the power or will (it isn't their core business at stake) to make a buck off other people's innovations. I think someone should call Microsoft's bluff already.