Methods of knowledge discovery in tweets.

The purposes of this methodological paper are: 1) to describe web mining methods for knowledge discovery in Tweets, and 2) to illustrate application of the methods using the topic of physical activity. Methods described include: 1) structure mining to discover structures (macro-, meso-, and micro-level) of Tweet networks using social network analysis, and 2) content mining to discover Tweet contents using n-gram based text analysis and sentiment analysis. Specific web mining tools for each step of the web mining process (e.g., NodeXL, ORA, Pajek, Weka) are detailed. Our novel application of web mining methods was useful in understanding multiple dimensions of physical activity. The methods that we applied may be useful to others wishing to mine social media for health-related purposes.