Diversity in Microblogging

While writing the book chapter on “Twitter as Serendipitous Learning Space”, I have come across an interesting research paper titled “The Wisdom in Tweetonomies”, in which Wagner and Strohmaier (2010) propose several measures of diversity in microblogging. These include:

• social diversity (variety of users authoring a stream)
• conversational diversity (number of users communicating via a stream)
• lexical diversity (the vocabulary size of a stream)
• topical diversity (such as use of hashtags)
• informational diversity (number of unique links)
• spacial diversity (messages from different locations)
• temporal diversity (messages published at different moments in time)

Maybe you know some other measures of diversity in microblogging? It would be great if you could post a link

Wagner, C. and Strohmaier, M. (2010), The Wisdom in Tweetonomies: Acquiring Latent Conceptual Structures, Semantic Search Workshop, WWW2012. URL: http://km.aifb.kit.edu/ws/semsearch10/Files/tweet.pdf