Bookmark using device, bookmark creation device, bookmark sharing system, control method, control program, and recording medium

A bookmark using device provided with: a feature information extraction unit (64) which extracts feature information from a bookmark, said bookmark at least including a content acquisition address for acquiring content and feature information representing the details of the content; and a substitute content search unit (65) which, based on the extracted feature information, finds substitute content with details that are similar or equivalent to the details of the above content from one or a plurality of content sources which supply content usable by this device. Therefore, the bookmark using device is able to find where to obtain different accessible substitute content equivalent in detail to content registered in a bookmark.