the public to refer to Apple's music player so extensively that it falls under Apple's trademark cover. Such activity was speculated to be part of a bigger campaign for Apple to expand the scope of its existing iPod trademark, which included trademarking "IPOD", "IPODCAST", and "POD". On November 16, 2006, the Apple Trademark Department stated that "Apple does not object to third-party usage of the generic term 'podcast' to accurately refer to podcasting services" and that "Apple does not license the term". However, no statement was made as to whether or not Apple believed they held rights to it. Personal Audio lawsuits Personal Audio, a company referred to as a "patent troll" by the Electronic Frontier Foundation (EFF), filed a patent on podcasting in 2009 for a claimed invention in 1996. In February 2013, Personal Audio started suing high-profile podcasters for royalties, including The Adam Carolla Show and the HowStuffWorks podcast. In October 2013, the EFF filed a petition with the US Trademark Office to invalidate the Personal Audio patent. On August 18, 2014, the EFF announced that Adam Carolla had settled with Personal Audio. Finally, on April 10, 2015, the U.S. Patent and Trademark Office invalidated five provisions of Personal Audio's podcasting patent. Types of podcasts Podcasts vary in style, format, and topical content. Podcasts are partially patterned on previous media genres but depart from them systematically in certain computationally observable stylistic respects. The conventions and constraints which govern that variation are emerging and vary over time and markets; podcast listeners have various preferences of styles but conventions to address them and communicate about them are still unformed. Some current examples of types of podcasts are given below. This list is likely to change as new types of content, new technology to consume podcasts, and new use cases emerge. Enhanced podcasts An enhanced podcast, also known as a slidecast, is a type of podcast that combines audio with a slide show presentation. It is similar to a video podcast in that it combines dynamically generated imagery with audio synchronization, but it is different in that it uses presentation software to create the imagery and the sequence of display separately from the time of the original audio podcast recording. The Free Dictionary, YourDictionary, and PC Magazine define an enhanced podcast as "an electronic slide show delivered as a podcast". Enhanced podcasts are podcasts that incorporate graphics and chapters. iTunes developed