CONF Negoescu_ACMMM10_2010/IDIAP Kodak Moments and Flickr Diamonds: How Users Shape Large-scale Media Negoescu, Radu-Andrei Loui, Alexander Gatica-Perez, Daniel https://publications.idiap.ch/index.php/publications/showcite/Negoescu_Idiap-RR-20-2010 Related documents Proc. of the 18th Intl. Conf. on Multimedia Firenze, Italy 2010 Firenze, Italy October 2010 REPORT Negoescu_Idiap-RR-20-2010/IDIAP Kodak Moments and Flickr Diamonds: How Users Shape Large-scale Media Negoescu, Radu-Andrei Loui, Alexander Gatica-Perez, Daniel EXTERNAL https://publications.idiap.ch/attachments/reports/2010/Negoescu_Idiap-RR-20-2010.pdf PUBLIC Idiap-RR-20-2010 2010 Idiap July 2010 In today's age of digital multimedia deluge, a clear understanding of the dynamics of online communities is capital. Users have abandoned their role of passive consumers and are now the driving force behind large-scale media repositories, whose dynamics and shaping factors are not yet fully understood. In this paper we present a novel human-centered analysis of two major photo sharing websites, Flickr and Kodak Gallery. On a combined dataset of over 5 million tagged photos, we investigate fundamental differences and similarities at the level of tag usage and propose a joint probabilistic topic model to provide further insight into semantic differences between the two communities. Our results show that the effects of the users' motivations and needs can be strongly observed in this large-scale data, in the form of what we call Kodak Moments and Flickr Diamonds. They are an indication that system designers should carefully take into account the target audience and its needs.