A recommender system, also called a recommendation engine or content discovery platform is a type of information filtering system that aims to suggest items most relevant for some input or to a particular user.¹²³ In the context of social media, search engines, and other online services, a recommender system for a given service might sometimes informally but erroneously be referred to as the service's "algorithm". The use of recommender systems is pervasive, with commonly recognised examples including the generation of playlists for video and music streaming services, product recommendations for e-commerce platforms, and topics and individual items posted on social media platforms and the open web.⁴⁵ Online services employ machine learning or specialized deep learning recommendation models (DLRMs) that analyze user behavior and preferences to generate personalized content feeds for millions of users at any moment. The value of these systems becomes particularly evident in scenarios where users must select from a large number of options, such as products, media, or content.¹⁶ Suggestions are typically designed to shorten or work as a substitute for , including the selection of a product, musical selection, or online news source to read.