Online Social Networking (OSN) services have become among the most popular services on Internet and their growth has led to creation of lots of different applications and protocols. Most of these applications and protocols rely on findings of previous studies which were concentrated on analyzing and modeling of the structure of inferred friendship graph of social networks. However, serious questions have been raised about the significance of links in friendship graphs of different social networks. In this work, we present a measurement study on interactions occured in Flickr OSN. We show that a small portion of users consists a core and are responsible for most of the interactions on Flickr. We analyze the correlations between interactions and friendships, and observe that most of the interactions do not happen between friends. Furthermore, we investigate temporal properties of interactions and observe some insensitivity in results concerning the distribution of popularity (as a function of age) and age (as a function of popularity) of photos in Flickr. We see that this pattern emerges due to fast reaction of users to posted contents. Our results propose that links in friendship graph say little, if anything at all, about the level of activity of users in Flickr. Our findings also reveal patterns of interactions that can be used further in designing of new applications and protocols.