Chris Boggs, great guy and he helped out tremendously with SES Coverage, asked me to look at a thread at his forum. The thread is named URL Directories and asks if a shorter URL is better then a longer URL. So I looked back in my notes (this site) and found an entry named Length of a Domain Name which specifically discusses the domain name. But what about the URL structure? I couldn't find any entries here that discussed my humble opinion on that topic.
Talking within reason, having a URL that looks like: http://www.domain.com/blog/2005/08/22/where-is-carmen-sandiego versus http://www.domain.com/blog/where-is-carmen-sandiego
Will not make a noticeable difference in your rankings. What the engines mean when they say a shorter file path structure is in terms of site navigation. For example, if I literally have to click from the main site, to the blog, to the 2005 section, to the August section, to the 22nd day section and then click on where-is-carmen-sandiego - then that is bad. But if I put a link (i.e the first, long, one listed above) on the index page, to a long URL, then the search engines will crawl it and index it well. The shorter the click path to a specific file, the better off you are. The length of the URL itself, is not a major factor in terms of search engines.