What's so different about the net?

[JQ Johnson]

One of the many threads in the "cataloging the web" discussion observed
that the web contains much ephemeral material.  Stuart Weibel replied:

>  > 3) Ephemeral nature of material -- cataloged today, gone
>  >    tomorrow.
>My guess is that libraries will select more stable resources, of
>demonstrated value.

We should observe that many interesting web materials are ephemeral in
several different senses.  Some have a short useful life but hang
around forever (remember that "what's new" page you visited yesterday
with a "last modified Dec 1994" date stamp?  I'd say that by web
standards 1994 is forever ago!).  Many have a short lifespan, and they
are deleted after serving their purpose (perhaps leaving dangling
pointers to them elsewhere on the web).  Others, more interestingly, go
through rapid modification during their (potentially long) lifetimes.
Examples of the latter is <URL:http://www.cnn.com/> or the weather
forecast for a particular weather station from UIUC.  One problem for
traditional catalogers (the ones who know what MARC formats are) is
that there is not an obvious way to deal with web objects (let's say
URLs) that change perhaps each time we visit them.  Treat them as
"serials"?  Ignore them?  Ignore the fact that they change?  Wait for
someone else outside the library community to develop a different
notion of web "objects" (let's disingenously call them "URNs") with
more familiar properties?

I don't believe "stable resources" is currently well defined.