There's a seemingly sincere and therefore befuttlingly naieve proposal posted today on R/RW for standardizing the interwebs around keyword-rich and onto-logical URLs. A wonderful discussion happens in the comments on this page so do scroll downwards. I will likely repurpose some of this discussion for my class next winter...
It's a fun thing to think about... and let's not forget that SEO ppl have been using keyword-rich URLs in much the same manner that R/RW proposes for some time now. I've been informally experimenting with keyword-rich URLs for years now and it seems like the degree to which the major search engines' algorithms weigh keywords in the URL and/or domain name is governed by a knob that's twiddled-with constantly. Used to be a pretty big off-page optimization ... now not so much.

My name is Dan Klyn, and I'm an information architect.
I work with amazing people at a nonprofit company called Flannel in Grand Rapids, Michigan.
I also teach IA in the library science programs at the University of Michigan and at Wayne State University.