"But in other sectors, the present system functions as a tax on innovation. In IT, resources have been expended to build up huge portfolios of patents, most of which have little value in themselves but which collectively hold out some promise of defensive use or licensing potential. Patents are not ordinary assets; they are options to litigate. While patent lawyers and other intermediaries benefit directly from the scope and scale of IT patents, that volume represents potential liability for companies that market useful products. Most patents belong to others, and the sheer volume obscures the patent landscape, limits the ability to evaluate patents and inevitably leads to inadvertent infringement."