The patent claims domain over computer-based systems implementing the methods as well. A passage in the patent application reads: "In the coming months many digitized forms of entertainment will be available for downloading from the internet for a free. It is expected, for example, that Napster will charge a fee payable, in part, to the copyright holder of any music file that is copied. [...] Once digitalized forms of entertainment become available for copying from the internet at a reasonable fee, parents and other fund providers will want to control how much money their children/fund recipients spend per week or per month on obtaining copies of the entertainment [...]" Apple has filed its own iTunes patents in recent months. Most recent is a patent for determining the popularity of a source of serial (sequentially released) online content based upon a number of subscriptions to the source. In other words, the patent calls for a method that would allow Apple to track how popular a stream of content, from the iTunes Store for instance, is based on how many users currently subscribe to it. T Statistics in the suit suggest that Apple controls 75 percent of online video, 83 percent of online music, and over 90 percent of the hard-drive based media player market.