41 provision of audio, video, and other media and applications in electronic formats; distribution for others of audio, video, and other media and applications in electronic formats; aggregation of audio, video, and other media and applications in electronic formats for distribution by others; provision of audio, video, and other media and applications for consumption on handheld and mobile devices; distribution for others of audio, video, and other media and applications for consumption on handheld and mobile devices; provision of search engines and other discovery tools in the field of audio, video, and other media and applications; provision of suggestions and recommendations in the field of audio, video, and other media and applications; provision of filtering, ranking, and other user feedback-based tools in the field of audio, video, and other media and applications; provision of policy-based content filtering and management tools and services; providing computer software for making audio, video, and other media interoperable with content distribution networks; providing developers of audio, video, and other media and applications services for signing and authenticating such media to assign and recognize the relationship between developers and their media