Social media (e.g., Twitter and FaceBook) have been one of the most popular online communication channels to share information among users. It means the users can give (and have) cognitive influences to (and from) the others. Thus, it is important for many online collaborative applications to understand how the information can be propagated via such social media. In this paper, we focus on a social tagging system where users can easily exchange resources as well as their tags with other users. Given a certain tag from a temporal folksonomy, the social pulse can be established by counting the number of users (or resources). Particularly, we can discover meaningful relationship between tags by computing inducibility. To conduct experimentation, a tag search system has been implemented to collect a dataset from Flickr.