Google did some research in 2000 where they spidered the top 100 pages for popular queries. They then compiled a variety interesting metrics about the pages (such as document size, url length, average title length, file types, etc...).
The research was published as part of the Search Engine World Quarterly (Q3 2000).
Any one know of follow-up research? The article mentioned a phase 2 where they used the same data / methods but analyzed links. I'll try to track that down, but somehow I have doubts about finding it.
It might be interesting (and feasible) to update this study. It would be even more interesting to look at this on Globalspec and other verticals to see if it holds in a domain centric search engine. Do the same properties hold over time and in different types of web pages (i.e. blogs or engineering pages)?