  Social networks are a prominent feature of many social media sites, a new
generation of Web sites that allow users to create and share content. Sites
such as Digg, Flickr, and Del.icio.us allow users to designate others as
"friends" or "contacts" and provide a single-click interface to track friends'
activity. How are these social networks used? Unlike pure social networking
sites (e.g., LinkedIn and Facebook), which allow users to articulate their
online professional and personal relationships, social media sites are not, for
the most part, aimed at helping users create or foster online relationships.
Instead, we claim that social media users create social networks to express
their tastes and interests, and use them to filter the vast stream of new
submissions to find interesting content. Social networks, in fact, facilitate
new ways of interacting with information: what we call social browsing. Through
an extensive analysis of data from Digg and Flickr, we show that social
browsing is one of the primary usage modalities on these social media sites.
This finding has implications for how social media sites rate and personalize
content.
