The online social network field is broad, and any literature review can only focus on a selection of articles. The present article highlights recent research in the field and focuses on centrality, linkage strength, identity, trust, activity and benefits. By no means is this review comprehensive, but it should give practitioners some useful concepts to consider as they design social network based web applications.
An interesting article pointing out the theoretical concepts to leverage social networks. Article from Shiv Singh from Avenue|Razorfish.