The December UI Design Letter from Human Factors International has a great recap of “usability research findings”:http://www.humanfactors.com/downloads/dec05.asp#kath from the past few years.
The topics covered include areas such as the usefulness of breadcrumbs trails, whether users browse or search, how users respond to error messages, and so on.
For example, the study on breadcrumbs concludes:
bq. People who are taught about breadcrumbs tend to use them more often. However, users still do not use them spontaneously. (Hull, 2004)
Want to read the whole study? They’re all listed at the bottom of the article. If you find the full name of the study and Google it you’ll get to the original article. The one on breadcrumbs is titled “Influence of Training and Exposure on the Usage of Breadcrumb Navigation”:http://psychology.wichita.edu/surl/usabilitynews/61/breadcrumb.htm.