Online Social Networking (OSN) has become one of the main applications on the Internet. Pinterest is an emerging social network that is gaining a lot of popularity and mostly focuses on images. In this work, we crawled during several months the Pinterest website and collected all the relevant information to characterize this social network (e.g., users' profiles, publications and activities). More precisely, we investigate the interaction of users in Pinterest such as the type of activities, the published images and the lexical analysis of their descriptions.We study as well the importance of this OSN to leverage traffic into external websites. Throughout this paper, we emphasize on the specific characteristics of Pinterest with regards to other well-adopted OSN (Facebook and Twitter). In particular, Pinterest is a retransmission network, in which 84% of the publications comes directly from other users. This fact and the Pinterest architecture have a direct impact on website ranking in search engines. Finally, as Facebok or Twitter target social relationships or breaking news, Pinterest has a different nature and is mostly devoted to leisure and entertainment.