Coupling of distinct mechanisms.

<p>We plot the fraction of the social spreading, self-promotion, and broadcast links in diffusion trees deeper than a given threshold in <b>a</b>. The x-axis value is the lower bound of selected trees’ depth. In <b>b</b>, the distribution of the route number for each type is displayed. We calculate the average route number of the diffusion links for each type in diffusion trees deeper than a certain depth, and present the results in <b>c</b>. After removing the leaves of diffusion trees, we obtain the information diffusion skeletons. We show the average route number and composition in diffusion skeletons whose depth exceeds certain values in the main panel and inset of <b>d</b> respectively. In the spreading processes among population, the fraction and average route number of social spreading and broadcast links are presented in <b>e</b> and <b>f</b>.