Simply put - URLs decay or fail. Persistent Uniform Resource Locators, or PURLs, are symbolic names rather that actual locations. The PURL is kept in a PURL database independent of the URL's location. Dr. Weibel used his PURL as an example of how a PURL works. People using his PURL would not need to know about the change or be concerned about losing and seeking him again.
PURLs add a level of stability to the Internet and are based on standard protocols .
Thus far, there have been 350 downloads of the PURL code from OCLC's site. PURLs are a step towards URNs - Uniform Resource Names. Organizations such as libraries, governments, publishers, and corporate entities which have large numbers of online, long-life documents are interested in URNs. Thus far, organizations and governments such as W3C, the Library of Congress, Finland, and Stanford support PURLs. Workshop attendees were given a glimpse of the Internet as an orderly entity.