Our idea is to exploit the structure of repost tree together with content of messages to help distinguish two different messages on repost tree, i.e., leaders and followers.
leader is referred to as a message on repost tree covering salient new information, which can lead further comments or discussions in its descendant reposts; follower is referred to as a message that contains no comment, simply repeats or naively responds to its ancestor leader message, thus providing no important information.