document: Finding hierarchy in directed online social networks Social hierarchy and stratification among humans is a well studied concept in sociology . The popularity of online social networks presents an opportunity to study social hierarchy for different types of networks and at different scales . We adopt the premise that people form connections in a social network based on their perceived social hierarchy ; as a result , the edge directions in directed social networks can be leveraged to infer hierarchy . In this paper , we define a measure of hierarchy in a directed online social network , and present an efficient algorithm to compute this measure . We validate our measure using ground truth including Wikipedia notability score . We use this measure to study hierarchy in several directed online social networks including Twitter , Delicious , YouTube , Flickr , LiveJournal , and curated lists of several categories of people based on different occupations , and different organizations . Our experiments on different online social networks show how hierarchy emerges as we increase the size of the network . This is in contrast to random graphs , where the hierarchy decreases as the network size increases . Further , we show that the degree of stratification in a network increases very slowly as we increase the size of the graph .
doc_bio_tags: O B O O O B I O B O O O O O O O O O O O O O O O O B I O O O O O O B O O O O O O O O O O O O O O O O O O O O O O O O O O O B O O O O O O O O O O B I O O O O O B O O O O O O O O B O B O O O O O O O O O O O O O O O B O O O O B O O O O O O O O O O O B O O B O O O O B I O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B I O O B O O O O O O O O O O O O O O O O O O O O B O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O