What some Web providers fail to understand is that they don't need
to defeat caching every minute of every day of the year in order
to get an estimate of the number of visitors, or a significant sample
of clickstreams.
If that data is needed, just set up a couple cache-free days per
month per service. With a little statistical analysis, you will
get a far more accurate survey of user preferences than is achieved
by most marketing surveys, and at the same time you will improve
the average performance of your site.
Assuming the cache-free days are distributed randomly, this would
be considered "socially acceptable" behavior on the part of the
service provider, since everyone understands that they need to
make a living.
....Roy T. Fielding Department of ICS, University of California, Irvine USA
Visiting Scholar, MIT/LCS + World-Wide Web Consortium
(fielding@w3.org) (fielding@ics.uci.edu)