This document presents an association rule mining framework for discovering patterns in social network data from tweets. It collects and preprocesses tweets to remove unnecessary information and map them to a transactional database. Frequent itemsets are extracted using apriori mining and represented as association rules. A taxonomy is automatically generated from the rules and graph partitioning is used to make it more compact. Experimental results on a dataset about the European Union show the framework can effectively analyze user behavior and topic trends through the generated rules and taxonomy.