This chapter analyses the complex and multi-faceted linguistic processes which underlie the online communities of practice established around the Q+A sites is that of collocation networks. Collocation networks, a concept originally proposed by Phillips, are based on a very simple observation. Words in texts and discourse systematically co-occur to create a range of cross-associations that can be visualized as networks of nodes and collocates. The concept of collocation networks is best demonstrated with the following example, which is based on the Q+a corpus explored. The length of the arrows in the graph indicates the strength of the collocational relationship as measured by the selected association measure, in this case, the Mutual Information (MI) score; the arrow is inversely proportional to the strength of the collocation the shorter the arrow, the stronger the collocational relationship. A bidirectional arrow signifies a collocational relationship between two nodes that have been expanded for collocates.