You might have noticed tag clouds if you are into Web 2.0. I think they are an interesting widget on their own. With Owen Kaser, I wrote a paper on tag-cloud optimization. I expect this will be a popular topic. Our paper has a definitively hard component, with lots of (non-human) experimental evidence:
Tag clouds provide an aggregate of tag-usage statistics. They are typically sent as in-line HTML to browsers. However, display mechanisms suited for ordinary text are not ideal for tags, because font sizes may vary widely on a line. As well, the typical layout does not account for relationships that may be known between tags. This paper presents models and algorithms to improve the display of tag clouds that con- sist of in-line HTML, as well as algorithms that use nested tables to achieve a more general 2-dimensional layout in which tag relationships are considered. The first algorithms leverage prior work in typesetting and rectangle packing, whereas the second group of algorithms leverage prior work in Electronic Design Automation. Experiments show our algorithms can be efficiently implemented and perform well.
To appear in the proceedings of the Tagging and Metadata for Social Information Organization (WWW 2007) workshop.