How far and how fast does information spread in social media? Researchers
have recently examined a number of factors that affect information diffusion in
online social networks, including: the novelty of information, users' activity
levels, who they pay attention to, and how they respond to friends'
recommendations. Using URLs as markers of information, we carry out a detailed
study of retweeting, the primary mechanism by which information spreads on the
Twitter follower graph. Our empirical study examines how users respond to an
incoming stimulus, i.e., a tweet (message) from a friend, and reveals that
%retweeting behavior is constrained by a few simple principles. the "principle
of least effort" combined with limited attention plays a dominant role in
retweeting behavior. Specifically, we observe that users retweet information
when it is most visible, such as when it near the top of their Twitter stream.
Moreover, our measurements quantify how a user's limited attention is divided
among incoming tweets, providing novel evidence that highly connected
individuals are less likely to propagate an arbitrary tweet. Our study
indicates that the finite ability to process incoming information constrains
social contagion, and we conclude that rapid decay of visibility is the primary
barrier to information propagation online.

研究社交媒体信息扩散的速度和范围，认为信息的新奇性、用户活动水平、注意力集中和对好友推荐的反应等因素影响信息扩散，用户的所花的最小努力与有限的注意力是信息扩散中的支配性原则，高度连接的个体不太可能传播任意推文，高连接度并不一定导致信息有效传播。