Who Says What to Whom on Twitter Categories and Subject Descriptors

Abstract

We study several longstanding questions in media communi- cations research, in the context of the microblogging service Twitter, regarding the production, flow, and consumption of information. To do so, we exploit a recently introduced feature of Twitterknown as Twitter liststo distinguish between elite users, by which we mean specifically celebri- ties, bloggers, and representatives ofmedia outlets and other formal organizations, and ordinary users. Based on this clas- sification, we find a striking concentration of attention on Twitterroughly 50% of tweets consumed are generated by just 20K elite userswhere the media produces the most in- formation, but celebrities are the most followed. We also find significant homophily within categories: celebrities listen to celebrities, while bloggers listen to bloggers etc; however, bloggers in general rebroadcast more information than the other categories. Next we re-examine the classical two-step flow theory of communications, finding considerable sup- port for it on Twitter, but also some interesting differences. Third, we find that URLs broadcast by different categories of users or containing different types of content exhibit sys- tematically different lifespans. And finally, we examine the attention paid by the different user categories to different news topics.