Last I read, URL is being dropped from technical documents. At http://www.w3.org/Addressing/ "URL Uniform Resource Locator. An informal term (no longer used in technical specifications) associated with popular URI schemes: http, ftp, mailto, etc." Also http://www.w3.org/Addressing/9710-uri-vs-url.html.

I find what you mentioned in the 1998 spec, and I guess the "cool URLs don't change!" backlash drove the quest that things on the web be URI's, not something that happens to be the current location but might change.