From the website...
A PURL is a Persistent Uniform Resource Locator. Functionally, a PURL is a [UniformResourceLocator]. However, instead of pointing directly to the location of an Internet resource, a PURL points to an intermediate resolution service. The PURL resolution service associates the PURL with the actual URL and returns that URL to the client. The client can then complete the URL transaction in the normal fashion. In Web parlance, this is a standard HTTP redirect.
Basically, it adds a layer of indirection between the target site and the fetch request so that you can change the absolute address of the target (say, from http://www.example.com to http://www.example.net but still refer to it by the same name (say, "example").
Just like how the DomainNameService adds a layer of indirection between the fetch and IPs by using a gigantic lookup table (the DNS database).
PURLs of local interest:
- Meatball homepage
- http://purl.org/NET/meatball
- SunirShah's homepage
- http://purl.org/NET/sunir - old site
- MoinMoin
- http://purl.net/wiki/moin/ - trailing slash required
Is [Short URL] similar to PURL? just with advertising responsibilities?