Effect on network structure.

<p><b>(A)</b> Response probability <i>p</i> versus structure of source user <i>u</i>_<i>s</i> and be-mentioned user <i>u</i>_<i>m</i>. <b>(B)</b> Response probability <i>p</i> versus structure of two be-mentioned users <i>u</i>_<i>m</i>1 and <i>u</i>_<i>m</i>2. From (a)(b), we can both observe that the response probability is the highest when a reciprocal followship exists between users. <b>(C)</b> Response probability <i>p</i> versus degree ratio , where <i>d</i>(<i>u</i>_<i>m</i>) represents the number of followers of be-mentioned user <i>u</i>_<i>m</i> and <i>d</i>(<i>u</i>_<i>s</i>) is the number of followers of source user <i>u</i>_<i>s</i>. We find that the response probability of the degree ratio between [0.1, 10) is higher than the others.