Please explain in more details, that will be more helpful. 
It has been a while. Back to 2007, I checked PURL's architecture, and it was straightly handling web addresses only. Of course, current HTTP protocol is not going to last forever, and there are other protocols in the Internet. The coverage of PURL is not enough. 
From PURL's website, it still says " PURLs (Persistent Uniform Resource Locators) are Web addresses that act as permanent identifiers in the face of a dynamic and changing Web infrastructure." I am not sure what "web addresses" means.  http://www.purl.org/docs/help.html#overview says " PURLs are Persistent Uniform Resource Locators (URLs). A URL is simply an address on the World Wide Web". We all know that "World Wide Web" is not "the Internet". What if info resource can be accessed through other Internet Protocols (FTP, VOIP, ....)?  This is the limitation of PURL. 
PURL is doing re-architecture, though I cannot find out more documentation.
The Handle system is " The Handle System is a general purpose distributed information system that provides efficient, extensible, and secure HDL identifier and resolution services for use on networks such as the Internet.". http://www.handle.net/index.html Notice the difference in definition. 

Yan


-----Original Message-----
From: Code for Libraries [mailto:[log in to unmask]] On Behalf Of Ross Singer
Sent: Wednesday, November 18, 2009 8:11 PM
To: [log in to unmask]
Subject: Re: [CODE4LIB] Assigning DOI for local content

On Wed, Nov 18, 2009 at 12:19 PM, Han, Yan <[log in to unmask]> wrote:
> Currently DOI uses Handle (technology) with it social framework (i.e. administrative body to manage DOI). In technical sense, PURL is not going to last long.

I'm not entirely sure what this is supposed to mean (re: purl), but
I'm pretty sure it's not true.

I'm also pretty sure there's little to no direct connection between
purl and doi despite a superficial similarity in scope.

-Ross.