A new analysis of data from del.ici.ous shows that, while the number of tags grows roughly in proportion to the growth of content, users can unwittingly provide bridges between networks of seemingly unrelated concepts.
Sometimes I want to have some means of structuring my tag cloud. For example, I tag a lot of researchers' home pages with their last names as tag. So I want to have all these last names together in one spot.
U. Priss. Proceedings of the 17th International Conference on Conceptual Structures (ICCS 2009), volume 5662 of Lecture Notes in Computer Science, page 257-269. Springer, (2009)