I recently had the good fortune to collaborate with Mark Nottingham from Yahoo regarding some caching problems for some of their pages.
Mark has written a fine summation of the problem and offers a functional solution (gotta love those functional solutions) for scenarios where a proxy is caching something the web site admins don't want cached. Have a read; it's well worth your time.
http://www.mnot.net/blog/2009/02/24/unintended_caching
Jim HarrisonProgram Manager, FF Edge CS
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