Re: Caching Servers Considered Harmful (was: Re: Finger URL)

Sarr Blumson (
Mon, 22 Aug 1994 19:01:25 +0200

Rob Raisch, The Internet Company, says:

[Putting his publisher hat on]

Let's see how this goes if we substitute "book store" for "caching server"

Because anyone running a caching server runs the dual risk of presenting
out-of-date information to their users and can be in direct violation of
international copyright law.

Yes, a book store could sell the old edition or let its customers Xerox books
and never pay the publisher. Bookstores even get to return unsold books for
credit. For paperbacks, at least, they don't even have to return the whole
book, only the cover. They can (and some do) sell the rest (this is
physically possible, not legal).

The publisher holds complete responsibility over their product, in
content, presentation, timeliness and distribution. By running a caching
server on my content, you are robbing me of any control I might have over
the timeliness and distribution.

Yes, as does the bookstore.

You can provide no guarantee that the versions that you present to your
users are accurate or timely. Further, I have no idea of the number of
consumers who view my content through your cache or what they view, how
and when.


Even assuming that you are acting in good faith, there are many kinds of
information which have value because of their timeliness. Daily news and
stock quotes are two which immediately come to mind.

Yes, the bookstore should pull yesterday's newspapers and put out todays.

Of course, I can mark my information as being uncacheable, but will you
honor that request? Your interest is to provide content to your users
with as little impact on your communications resources as possible. I
believe that your goals and mine are not compatible.

Well, my bookstore would be a lot more profitable if I could get the New York
Times shipped by one week ground.

The copyright issue is the more difficult one. In light of the previous
argument, you are archiving an original work. This is called "copying"
in copyright law and if it is done without permission, is against the law.

If I have the book on my shelf without having gotten it through a legitimate
chain of transactions leading back to the publisher, I have also broken some


I expect that most professional publishers will not serve content to any
site which caches unless they can enter into a business relationship with
that site. Unfortunately, this presents a very interesting N by N
problem, as publishers and caching servers proliferate.

Yes, this is an issue for bookstores too, and all other forms of retail
commerce, actually. That's why wholesalers and distributors, the infamous
"middlemen" of common parlance, exist.

My flipness aside, there are issues here, but they are issues which are
amenable to technical solutions. There are lots of authentication mechanisms
for insuring that a publisher only "sells" to a "distributor" (cache) that she
trusts, and to sign time critical material to that it identifiable as reliably
as a newspaper is by the date on the top. If anything, our problem is
choosing among the alternatives, which is a problem largely because the
choosing may decide a lot of things about who get rich from this new

Sarr Blumson
voice: +1 313 764 0253 FAX: +1 313 763 4434
CITI, University of Michigan, 519 W William, Ann Arbor, MI 48103-4943