This paper analyses the tagging patterns on delicious.com for a set of documents (URLs) over a 4 year period using informetrics methods to assess how collaborative tagging supports and enhances traditional document indexing. Results of the study show that there is still a mix of consensus and divergence in tagging term use and tagging patterns. While some of the chosen URLs maintained or even increased their popularity, others experienced a severe drop in popularity. Tag usage showed some measures of influence between taggers, but users continued to use their own tags and the proportions of unique and untagged items has increased. Proportions of tags used showed fluctuations with islands of stability over a 4 year period. Patterns in the usage of tags assigned to these documents also highlighted practices related to personal and collective information organisation which conventional systems are unable to facilitate.